java.lang.Object
- java.lang.Enum<SqlKind>
- - org.apache.calcite.sql.SqlKind

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<SqlKind>
```
public enum SqlKind
extends java.lang.Enum<SqlKind>
```
Enumerates the possible types of SqlNode.
The values are immutable, canonical constants, so you can use Kinds to find particular types of expressions quickly. To identity a call to a common operator such as '=', use SqlNode.isA(java.util.Set<org.apache.calcite.sql.SqlKind>):

exp.isA(EQUALS)

Only commonly-used nodes have their own type; other nodes are of type OTHER. Some of the values, such as SET_QUERY, represent aggregates.

To quickly choose between a number of options, use a switch statement:
```
switch (exp.getKind()) {
 case EQUALS:
     ...;
 case NOT_EQUALS:
     ...;
 default:
     throw new AssertionError("unexpected");
 }
```
Note that we do not even have to check that a SqlNode is a SqlCall.

To identify a category of expressions, use SqlNode.isA with an aggregate SqlKind. The following expression will return true for calls to '=' and '>=', but false for the constant '5', or a call to '+':
```
exp.isA(SqlKind.COMPARISON)
```
RexNode also has a getKind method; SqlKind values are preserved during translation from SqlNode to RexNode, where applicable.

There is no water-tight definition of "common", but that's OK. There will always be operators that don't have their own kind, and for these we use the SqlOperator. But for really the common ones, e.g. the many places where we are looking for AND, OR and EQUALS, the enum helps.

(If we were using Scala, SqlOperator would be a case class, and we wouldn't need SqlKind. But we're not.)

Enum Constant Summary

Enum Constants
Enum Constant	Description
`ALL`	The "ALL" quantification operator.
`ALTER_INDEX`	`ALTER INDEX` DDL statement.
`ALTER_MATERIALIZED_VIEW`	`ALTER MATERIALIZED VIEW` DDL statement.
`ALTER_SEQUENCE`	`ALTER SEQUENCE` DDL statement.
`ALTER_SESSION`	`ALTER SESSION` DDL statement.
`ALTER_TABLE`	`ALTER TABLE` DDL statement.
`ALTER_VIEW`	`ALTER VIEW` DDL statement.
`AND`	The logical "AND" operator.
`ANY_VALUE`	The `ANY_VALUE` aggregate function.
`ARGUMENT_ASSIGNMENT`	ARGUMENT_ASSIGNMENT operator, `=>`
`ARRAY_QUERY_CONSTRUCTOR`	Array Query Constructor, e.g.
`ARRAY_VALUE_CONSTRUCTOR`	Array Value Constructor, e.g.
`AS`	AS operator
`ATTRIBUTE_DEF`	Attribute definition.
`AVG`	The `AVG` aggregate function.
`BETWEEN`	The "BETWEEN" operator.
`CASE`	A "CASE" expression.
`CAST`	The "CAST" operator.
`CEIL`	The "CEIL" function
`CHECK`	`CHECK` constraint.
`CLASSIFIER`
`COALESCE`	The "COALESCE" operator.
`COLLECT`	The `COLLECT` aggregate function.
`COLLECTION_TABLE`	Table operator which converts user-defined transform into a relation, for example, `select * from TABLE(udx(x, y, z))`.
`COLUMN_DECL`	Column declaration.
`COLUMN_LIST`	The non-standard constructor used to pass a COLUMN_LIST parameter to a user-defined transform.
`COMMIT`	`COMMIT` session control statement.
`CONTAINS`	The "CONTAINS" operator for periods.
`CORREL_VARIABLE`	Reference to correlation variable.
`COUNT`	The `COUNT` aggregate function.
`COVAR_POP`	The `COVAR_POP` aggregate function.
`COVAR_SAMP`	The `COVAR_SAMP` aggregate function.
`CREATE_FOREIGN_SCHEMA`	`CREATE FOREIGN SCHEMA` DDL statement.
`CREATE_FUNCTION`	`CREATE FUNCTION` DDL statement.
`CREATE_INDEX`	`CREATE INDEX` DDL statement.
`CREATE_MATERIALIZED_VIEW`	`CREATE MATERIALIZED VIEW` DDL statement.
`CREATE_SCHEMA`	`CREATE SCHEMA` DDL statement.
`CREATE_SEQUENCE`	`CREATE SEQUENCE` DDL statement.
`CREATE_TABLE`	`CREATE TABLE` DDL statement.
`CREATE_TYPE`	`CREATE TYPE` DDL statement.
`CREATE_VIEW`	`CREATE VIEW` DDL statement.
`CUBE`	The internal `CUBE` operator that occurs within a `GROUP BY` clause.
`CUME_DIST`	The `ROW_NUMBER` window function.
`CURRENT_VALUE`	The "CURRENT VALUE OF sequence" operator.
`CURSOR`	CURSOR constructor, for example, `select * from TABLE(udx(CURSOR(select ...), x, y, z))`
`DECODE`	The "DECODE" function (Oracle).
`DEFAULT`	DEFAULT operator
`DELETE`	DELETE statement
`DENSE_RANK`	The `DENSE_RANK` window function.
`DESCENDING`	DESC in ORDER BY.
`DESCRIBE_SCHEMA`	DESCRIBE SCHEMA statement
`DESCRIBE_TABLE`	DESCRIBE TABLE statement
`DIVIDE`	The arithmetic division operator, "/".
`DOT`	Dot
`DROP_FUNCTION`	`DROP FUNCTION` DDL statement.
`DROP_INDEX`	`DROP INDEX` DDL statement.
`DROP_MATERIALIZED_VIEW`	`DROP MATERIALIZED VIEW` DDL statement.
`DROP_SCHEMA`	`DROP SCHEMA` DDL statement.
`DROP_SEQUENCE`	`DROP SEQUENCE` DDL statement.
`DROP_TABLE`	`DROP TABLE` DDL statement.
`DROP_TYPE`	`DROP TYPE` DDL statement.
`DROP_VIEW`	`DROP VIEW` DDL statement.
`DYNAMIC_PARAM`	A dynamic parameter.
`EQUALS`	The equals operator, "=".
`ESCAPE`	Escape operator (always part of LIKE or SIMILAR TO expression).
`EXCEPT`	Except
`EXISTS`	The "EXISTS" operator.
`EXPLAIN`	EXPLAIN statement
`EXPLICIT_TABLE`	Explicit table, e.g.
`EXTEND`	The internal `EXTEND` operator that qualifies a table name in the `FROM` clause.
`EXTRACT`	The "EXTRACT" function.
`FIELD_ACCESS`	The field access operator, ".".
`FILTER`	FILTER operator
`FINAL`	Special functions in MATCH_RECOGNIZE.
`FIRST`
`FIRST_VALUE`	The `FIRST_VALUE` aggregate function.
`FLOOR`	The "FLOOR" function
`FOLLOWING`	The "FOLLOWING" qualifier of an interval end-point in a window specification.
`FOREIGN_KEY`	`FOREIGN KEY` constraint.
`FUSION`	The `FUSION` aggregate function.
`GREATER_THAN`	The greater-than operator, ">".
`GREATER_THAN_OR_EQUAL`	The greater-than-or-equal operator, ">=".
`GREATEST`	The "GREATEST" function (Oracle).
`GROUP_ID`	The `GROUP_ID()` function.
`GROUPING`	The `GROUPING(e, ...)` function.
`GROUPING_ID`	Deprecated. Use `GROUPING`.
`GROUPING_SETS`	The internal `GROUPING SETS` operator that occurs within a `GROUP BY` clause.
`HOP`	The `HOP` group function.
`HOP_END`	The `HOP_END` auxiliary function of the `HOP` group function.
`HOP_START`	The `HOP_START` auxiliary function of the `HOP` group function.
`IDENTIFIER`	Identifier
`IMMEDIATELY_PRECEDES`	The "IMMEDIATELY PRECEDES" operator for periods.
`IMMEDIATELY_SUCCEEDS`	The "IMMEDIATELY SUCCEEDS" operator for periods.
`IN`	The "IN" operator.
`INPUT_REF`	Reference to an input field.
`INSERT`	INSERT statement
`INTERSECT`	Intersect
`IS_DISTINCT_FROM`	The is-distinct-from operator.
`IS_FALSE`	The "IS FALSE" operator.
`IS_NOT_DISTINCT_FROM`	The is-not-distinct-from operator.
`IS_NOT_FALSE`	The "IS NOT FALSE" operator.
`IS_NOT_NULL`	The "IS NOT NULL" operator.
`IS_NOT_TRUE`	The "IS NOT TRUE" operator.
`IS_NULL`	The "IS NULL" operator.
`IS_TRUE`	The "IS TRUE" operator.
`IS_UNKNOWN`	The "IS UNKNOWN" operator.
`JDBC_FN`	Call to a function using JDBC function syntax.
`JOIN`	JOIN operator or compound FROM clause.
`JSON_API_COMMON_SYNTAX`	The JSON API common syntax.
`JSON_ARRAYAGG`	The `JSON_ARRAYAGG` aggregate function.
`JSON_OBJECTAGG`	The `JSON_OBJECTAGG` aggregate function.
`JSON_VALUE_EXPRESSION`	The JSON value expression.
`LAG`	The `LAG` aggregate function.
`LAST`
`LAST_VALUE`	The `LAST_VALUE` aggregate function.
`LATERAL`	The "LATERAL" qualifier to relations in the FROM clause.
`LEAD`	The `LEAD` aggregate function.
`LEAST`	The "LEAST" function (Oracle).
`LESS_THAN`	The less-than operator, "<".
`LESS_THAN_OR_EQUAL`	The less-than-or-equal operator, "<=".
`LIKE`	The "LIKE" operator.
`LITERAL`	A literal.
`LITERAL_CHAIN`	Literal chain operator (for composite string literals).
`LOCAL_REF`	Reference to a sub-expression computed within the current relational operator.
`LTRIM`	The "LTRIM" function (Oracle).
`MAP_QUERY_CONSTRUCTOR`	Map Query Constructor, e.g.
`MAP_VALUE_CONSTRUCTOR`	Map Value Constructor, e.g.
`MATCH_NUMBER`
`MATCH_RECOGNIZE`	MATCH_RECOGNIZE clause
`MAX`	The `MAX` aggregate function.
`MERGE`	MERGE statement
`MIN`	The `MIN` aggregate function.
`MINUS`	The arithmetic minus operator, "-".
`MINUS_PREFIX`	The unary minus operator, as in "-1".
`MOD`	The arithmetic remainder operator, "MOD" (and "%" in some dialects).
`MULTISET_QUERY_CONSTRUCTOR`	The MULTISET query constructor.
`MULTISET_VALUE_CONSTRUCTOR`	The MULTISET value constructor.
`NEW_SPECIFICATION`	NewSpecification
`NEXT`
`NEXT_VALUE`	The "NEXT VALUE OF sequence" operator.
`NOT`	The logical "NOT" operator.
`NOT_EQUALS`	The not-equals operator, "!=" or "<>".
`NOT_IN`	The "NOT IN" operator.
`NTH_VALUE`	The `NTH_VALUE` aggregate function.
`NTILE`	The `NTILE` aggregate function.
`NULLIF`	The "NULLIF" operator.
`NULLS_FIRST`	NULLS FIRST clause in ORDER BY.
`NULLS_LAST`	NULLS LAST clause in ORDER BY.
`NVL`	The "NVL" function (Oracle).
`OR`	The logical "OR" operator.
`ORDER_BY`	ORDER BY clause.
`OTHER`	Expression not covered by any other `SqlKind` value.
`OTHER_DDL`	DDL statement not handled above.
`OTHER_FUNCTION`	Function that is not a special function.
`OVER`	OVER operator
`OVERLAPS`	The "OVERLAPS" operator for periods.
`PATTERN_ALTER`	the alternation operator in a pattern expression within a match_recognize clause
`PATTERN_CONCAT`	the concatenation operator in a pattern expression within a match_recognize clause
`PATTERN_EXCLUDED`	The special patterns to exclude enclosing pattern from output in a MATCH_RECOGNIZE clause.
`PATTERN_INPUT_REF`	Reference to an input field, with pattern var as modifier
`PATTERN_PERMUTE`	The internal "permute" function in a MATCH_RECOGNIZE clause.
`PATTERN_QUANTIFIER`	the repetition quantifier of a pattern factor in a match_recognize clause.
`PERCENT_RANK`	The `PERCENT_RANK` window function.
`PERIOD_EQUALS`	The "EQUALS" operator for periods.
`PLUS`	The arithmetic plus operator, "+".
`PLUS_PREFIX`	The unary plus operator, as in "+1".
`PRECEDES`	The "PRECEDES" operator for periods.
`PRECEDING`	The "PRECEDING" qualifier of an interval end-point in a window specification.
`PREV`
`PRIMARY_KEY`	`PRIMARY KEY` constraint.
`PROCEDURE_CALL`	ProcedureCall
`RANK`	The `RANK` window function.
`REGR_COUNT`	The `REGR_COUNT` aggregate function.
`REGR_SXX`	The `REGR_SXX` aggregate function.
`REGR_SYY`	The `REGR_SYY` aggregate function.
`REINTERPRET`	The internal REINTERPRET operator (meaning a reinterpret cast).
`ROLLBACK`	`ROLLBACK` session control statement.
`ROLLUP`	The internal `ROLLUP` operator that occurs within a `GROUP BY` clause.
`ROW`	The row-constructor function.
`ROW_NUMBER`	The `ROW_NUMBER` window function.
`RTRIM`	The "RTRIM" function (Oracle).
`RUNNING`
`SCALAR_QUERY`	Scalar query; that is, a sub-query used in an expression context, and returning one row and one column.
`SELECT`	SELECT statement or sub-query.
`SESSION`	The `SESSION` group function.
`SESSION_END`	The `SESSION_END` auxiliary function of the `SESSION` group function.
`SESSION_START`	The `SESSION_START` auxiliary function of the `SESSION` group function.
`SET_OPTION`	"ALTER scope SET option = value" statement.
`SIMILAR`	The "SIMILAR" operator.
`SINGLE_VALUE`	The `SINGLE_VALUE` aggregate function.
`SKIP_TO_FIRST`	The "SKIP TO FIRST" qualifier of restarting point in a MATCH_RECOGNIZE clause.
`SKIP_TO_LAST`	The "SKIP TO LAST" qualifier of restarting point in a MATCH_RECOGNIZE clause.
`SOME`	The "SOME" quantification operator (also called "ANY").
`STDDEV_POP`	The `STDDEV_POP` aggregate function.
`STDDEV_SAMP`	The `STDDEV_SAMP` aggregate function.
`SUCCEEDS`	The "SUCCEEDS" operator for periods.
`SUM`	The `SUM` aggregate function.
`SUM0`	The `SUM0` aggregate function.
`TABLE_INPUT_REF`	Reference to an input field, with a qualified name and an identifier
`TABLESAMPLE`	TABLESAMPLE operator
`TIMES`	The arithmetic multiplication operator, "*".
`TIMESTAMP_ADD`	The "TIMESTAMP_ADD" function (ODBC, SQL Server, MySQL).
`TIMESTAMP_DIFF`	The "TIMESTAMP_DIFF" function (ODBC, SQL Server, MySQL).
`TRIM`	The "TRIM" function.
`TUMBLE`	The `TUMBLE` group function.
`TUMBLE_END`	The `TUMBLE_END` auxiliary function of the `TUMBLE` group function.
`TUMBLE_START`	The `TUMBLE_START` auxiliary function of the `TUMBLE` group function.
`UNION`	Union
`UNIQUE`	`UNIQUE` constraint.
`UNNEST`	The "UNNEST" operator.
`UPDATE`	UPDATE statement
`VALUES`	The "VALUES" operator.
`VAR_POP`	The `VAR_POP` aggregate function.
`VAR_SAMP`	The `VAR_SAMP` aggregate function.
`WINDOW`	Window specification
`WITH`	WITH clause.
`WITH_ITEM`	Item in WITH clause.
`WITHIN_GROUP`	WITHIN_GROUP operator

Field Summary

Fields
Modifier and Type	Field	Description
`static java.util.EnumSet<SqlKind>`	`AGGREGATE`	Category consisting of all built-in aggregate functions.
`static java.util.Set<SqlKind>`	`AVG_AGG_FUNCTIONS`	Category of SqlAvgAggFunction.
`static java.util.Set<SqlKind>`	`COMPARISON`	Category of comparison operators.
`static java.util.Set<SqlKind>`	`COVAR_AVG_AGG_FUNCTIONS`	Category of SqlCovarAggFunction.
`static java.util.EnumSet<SqlKind>`	`DDL`	Category consisting of all DDL operators.
`static java.util.EnumSet<SqlKind>`	`DML`	Category consisting of all DML operators.
`static java.util.Set<SqlKind>`	`EXPRESSION`	Category consisting of all expression operators.
`static java.util.Set<SqlKind>`	`FUNCTION`	Category consisting of regular and special functions.
`java.lang.String`	`lowerName`	Lower-case name.
`static java.util.EnumSet<SqlKind>`	`QUERY`	Category consisting of query node types.
`static java.util.EnumSet<SqlKind>`	`SET_QUERY`	Category consisting of set-query node types.
`java.lang.String`	`sql`
`static java.util.EnumSet<SqlKind>`	`TOP_LEVEL`	Category of all SQL statement types.

Constructor Summary

Constructors
Modifier Constructor Description

private SqlKind()

private SqlKind(java.lang.String sql)

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`belongsTo(java.util.Collection<SqlKind> category)`	Returns whether this `SqlKind` belongs to a given category.
`private static <E extends java.lang.Enum<E>> java.util.EnumSet<E>`	`concat(java.util.EnumSet<E> set0, java.util.EnumSet<E>... sets)`
`SqlKind`	`negate()`	Returns the kind that you get if you apply NOT to this kind.
`SqlKind`	`negateNullSafe()`	Returns the kind that you get if you negate this kind.
`SqlKind`	`reverse()`	Returns the kind that corresponds to this operator but in the opposite direction.
`static SqlKind`	`valueOf(java.lang.String name)`	Returns the enum constant of this type with the specified name.
`static SqlKind[]`	`values()`	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum
clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Enum Constant Detail
  - OTHER
```
public static final SqlKind OTHER
```
    Expression not covered by any other SqlKind value.
    
    See Also:
    
    OTHER_FUNCTION
  - SELECT
```
public static final SqlKind SELECT
```
    SELECT statement or sub-query.
  - JOIN
```
public static final SqlKind JOIN
```
    JOIN operator or compound FROM clause.
    A FROM clause with more than one table is represented as if it were a join. For example, "FROM x, y, z" is represented as "JOIN(x, JOIN(x, y))".
  - IDENTIFIER
```
public static final SqlKind IDENTIFIER
```
    Identifier
  - LITERAL
```
public static final SqlKind LITERAL
```
    A literal.
  - OTHER_FUNCTION
```
public static final SqlKind OTHER_FUNCTION
```
    Function that is not a special function.
    
    See Also:
    
    FUNCTION
  - EXPLAIN
```
public static final SqlKind EXPLAIN
```
    EXPLAIN statement
  - DESCRIBE_SCHEMA
```
public static final SqlKind DESCRIBE_SCHEMA
```
    DESCRIBE SCHEMA statement
  - DESCRIBE_TABLE
```
public static final SqlKind DESCRIBE_TABLE
```
    DESCRIBE TABLE statement
  - INSERT
```
public static final SqlKind INSERT
```
    INSERT statement
  - DELETE
```
public static final SqlKind DELETE
```
    DELETE statement
  - UPDATE
```
public static final SqlKind UPDATE
```
    UPDATE statement
  - SET_OPTION
```
public static final SqlKind SET_OPTION
```
    "ALTER scope SET option = value" statement.
  - DYNAMIC_PARAM
```
public static final SqlKind DYNAMIC_PARAM
```
    A dynamic parameter.
  - ORDER_BY
```
public static final SqlKind ORDER_BY
```
    ORDER BY clause.
    
    See Also:
    
    DESCENDING, NULLS_FIRST, NULLS_LAST
  - WITH
```
public static final SqlKind WITH
```
    WITH clause.
  - WITH_ITEM
```
public static final SqlKind WITH_ITEM
```
    Item in WITH clause.
  - UNION
```
public static final SqlKind UNION
```
    Union
  - EXCEPT
```
public static final SqlKind EXCEPT
```
    Except
  - INTERSECT
```
public static final SqlKind INTERSECT
```
    Intersect
  - AS
```
public static final SqlKind AS
```
    AS operator
  - ARGUMENT_ASSIGNMENT
```
public static final SqlKind ARGUMENT_ASSIGNMENT
```
    ARGUMENT_ASSIGNMENT operator, =>
  - DEFAULT
```
public static final SqlKind DEFAULT
```
    DEFAULT operator
  - OVER
```
public static final SqlKind OVER
```
    OVER operator
  - FILTER
```
public static final SqlKind FILTER
```
    FILTER operator
  - WITHIN_GROUP
```
public static final SqlKind WITHIN_GROUP
```
    WITHIN_GROUP operator
  - WINDOW
```
public static final SqlKind WINDOW
```
    Window specification
  - MERGE
```
public static final SqlKind MERGE
```
    MERGE statement
  - TABLESAMPLE
```
public static final SqlKind TABLESAMPLE
```
    TABLESAMPLE operator
  - MATCH_RECOGNIZE
```
public static final SqlKind MATCH_RECOGNIZE
```
    MATCH_RECOGNIZE clause
  - TIMES
```
public static final SqlKind TIMES
```
    The arithmetic multiplication operator, "*".
  - DIVIDE
```
public static final SqlKind DIVIDE
```
    The arithmetic division operator, "/".
  - MOD
```
public static final SqlKind MOD
```
    The arithmetic remainder operator, "MOD" (and "%" in some dialects).
  - PLUS
```
public static final SqlKind PLUS
```
    The arithmetic plus operator, "+".
    
    See Also:
    
    PLUS_PREFIX
  - MINUS
```
public static final SqlKind MINUS
```
    The arithmetic minus operator, "-".
    
    See Also:
    
    MINUS_PREFIX
  - PATTERN_ALTER
```
public static final SqlKind PATTERN_ALTER
```
    the alternation operator in a pattern expression within a match_recognize clause
  - PATTERN_CONCAT
```
public static final SqlKind PATTERN_CONCAT
```
    the concatenation operator in a pattern expression within a match_recognize clause
  - IN
```
public static final SqlKind IN
```
    The "IN" operator.
  - NOT_IN
```
public static final SqlKind NOT_IN
```
    The "NOT IN" operator.
    Only occurs in SqlNode trees. Is expanded to NOT(IN ...) before entering RelNode land.
  - LESS_THAN
```
public static final SqlKind LESS_THAN
```
    The less-than operator, "<".
  - GREATER_THAN
```
public static final SqlKind GREATER_THAN
```
    The greater-than operator, ">".
  - LESS_THAN_OR_EQUAL
```
public static final SqlKind LESS_THAN_OR_EQUAL
```
    The less-than-or-equal operator, "<=".
  - GREATER_THAN_OR_EQUAL
```
public static final SqlKind GREATER_THAN_OR_EQUAL
```
    The greater-than-or-equal operator, ">=".
  - EQUALS
```
public static final SqlKind EQUALS
```
    The equals operator, "=".
  - NOT_EQUALS
```
public static final SqlKind NOT_EQUALS
```
    The not-equals operator, "!=" or "<>". The latter is standard, and preferred.
  - IS_DISTINCT_FROM
```
public static final SqlKind IS_DISTINCT_FROM
```
    The is-distinct-from operator.
  - IS_NOT_DISTINCT_FROM
```
public static final SqlKind IS_NOT_DISTINCT_FROM
```
    The is-not-distinct-from operator.
  - OR
```
public static final SqlKind OR
```
    The logical "OR" operator.
  - AND
```
public static final SqlKind AND
```
    The logical "AND" operator.
  - DOT
```
public static final SqlKind DOT
```
    Dot
  - OVERLAPS
```
public static final SqlKind OVERLAPS
```
    The "OVERLAPS" operator for periods.
  - CONTAINS
```
public static final SqlKind CONTAINS
```
    The "CONTAINS" operator for periods.
  - PRECEDES
```
public static final SqlKind PRECEDES
```
    The "PRECEDES" operator for periods.
  - IMMEDIATELY_PRECEDES
```
public static final SqlKind IMMEDIATELY_PRECEDES
```
    The "IMMEDIATELY PRECEDES" operator for periods.
  - SUCCEEDS
```
public static final SqlKind SUCCEEDS
```
    The "SUCCEEDS" operator for periods.
  - IMMEDIATELY_SUCCEEDS
```
public static final SqlKind IMMEDIATELY_SUCCEEDS
```
    The "IMMEDIATELY SUCCEEDS" operator for periods.
  - PERIOD_EQUALS
```
public static final SqlKind PERIOD_EQUALS
```
    The "EQUALS" operator for periods.
  - LIKE
```
public static final SqlKind LIKE
```
    The "LIKE" operator.
  - SIMILAR
```
public static final SqlKind SIMILAR
```
    The "SIMILAR" operator.
  - BETWEEN
```
public static final SqlKind BETWEEN
```
    The "BETWEEN" operator.
  - CASE
```
public static final SqlKind CASE
```
    A "CASE" expression.
  - NULLIF
```
public static final SqlKind NULLIF
```
    The "NULLIF" operator.
  - COALESCE
```
public static final SqlKind COALESCE
```
    The "COALESCE" operator.
  - DECODE
```
public static final SqlKind DECODE
```
    The "DECODE" function (Oracle).
  - NVL
```
public static final SqlKind NVL
```
    The "NVL" function (Oracle).
  - GREATEST
```
public static final SqlKind GREATEST
```
    The "GREATEST" function (Oracle).
  - LEAST
```
public static final SqlKind LEAST
```
    The "LEAST" function (Oracle).
  - TIMESTAMP_ADD
```
public static final SqlKind TIMESTAMP_ADD
```
    The "TIMESTAMP_ADD" function (ODBC, SQL Server, MySQL).
  - TIMESTAMP_DIFF
```
public static final SqlKind TIMESTAMP_DIFF
```
    The "TIMESTAMP_DIFF" function (ODBC, SQL Server, MySQL).
  - NOT
```
public static final SqlKind NOT
```
    The logical "NOT" operator.
  - PLUS_PREFIX
```
public static final SqlKind PLUS_PREFIX
```
    The unary plus operator, as in "+1".
    
    See Also:
    
    PLUS
  - MINUS_PREFIX
```
public static final SqlKind MINUS_PREFIX
```
    The unary minus operator, as in "-1".
    
    See Also:
    
    MINUS
  - EXISTS
```
public static final SqlKind EXISTS
```
    The "EXISTS" operator.
  - SOME
```
public static final SqlKind SOME
```
    The "SOME" quantification operator (also called "ANY").
  - ALL
```
public static final SqlKind ALL
```
    The "ALL" quantification operator.
  - VALUES
```
public static final SqlKind VALUES
```
    The "VALUES" operator.
  - EXPLICIT_TABLE
```
public static final SqlKind EXPLICIT_TABLE
```
    Explicit table, e.g. select * from (TABLE t) or TABLE t. See also COLLECTION_TABLE.
  - SCALAR_QUERY
```
public static final SqlKind SCALAR_QUERY
```
    Scalar query; that is, a sub-query used in an expression context, and returning one row and one column.
  - PROCEDURE_CALL
```
public static final SqlKind PROCEDURE_CALL
```
    ProcedureCall
  - NEW_SPECIFICATION
```
public static final SqlKind NEW_SPECIFICATION
```
    NewSpecification
  - FINAL
```
public static final SqlKind FINAL
```
    Special functions in MATCH_RECOGNIZE.
  - RUNNING
```
public static final SqlKind RUNNING
```
  - PREV
```
public static final SqlKind PREV
```
  - NEXT
```
public static final SqlKind NEXT
```
  - FIRST
```
public static final SqlKind FIRST
```
  - LAST
```
public static final SqlKind LAST
```
  - CLASSIFIER
```
public static final SqlKind CLASSIFIER
```
  - MATCH_NUMBER
```
public static final SqlKind MATCH_NUMBER
```
  - SKIP_TO_FIRST
```
public static final SqlKind SKIP_TO_FIRST
```
    The "SKIP TO FIRST" qualifier of restarting point in a MATCH_RECOGNIZE clause.
  - SKIP_TO_LAST
```
public static final SqlKind SKIP_TO_LAST
```
    The "SKIP TO LAST" qualifier of restarting point in a MATCH_RECOGNIZE clause.
  - DESCENDING
```
public static final SqlKind DESCENDING
```
    DESC in ORDER BY. A parse tree, not a true expression.
  - NULLS_FIRST
```
public static final SqlKind NULLS_FIRST
```
    NULLS FIRST clause in ORDER BY. A parse tree, not a true expression.
  - NULLS_LAST
```
public static final SqlKind NULLS_LAST
```
    NULLS LAST clause in ORDER BY. A parse tree, not a true expression.
  - IS_TRUE
```
public static final SqlKind IS_TRUE
```
    The "IS TRUE" operator.
  - IS_FALSE
```
public static final SqlKind IS_FALSE
```
    The "IS FALSE" operator.
  - IS_NOT_TRUE
```
public static final SqlKind IS_NOT_TRUE
```
    The "IS NOT TRUE" operator.
  - IS_NOT_FALSE
```
public static final SqlKind IS_NOT_FALSE
```
    The "IS NOT FALSE" operator.
  - IS_UNKNOWN
```
public static final SqlKind IS_UNKNOWN
```
    The "IS UNKNOWN" operator.
  - IS_NULL
```
public static final SqlKind IS_NULL
```
    The "IS NULL" operator.
  - IS_NOT_NULL
```
public static final SqlKind IS_NOT_NULL
```
    The "IS NOT NULL" operator.
  - PRECEDING
```
public static final SqlKind PRECEDING
```
    The "PRECEDING" qualifier of an interval end-point in a window specification.
  - FOLLOWING
```
public static final SqlKind FOLLOWING
```
    The "FOLLOWING" qualifier of an interval end-point in a window specification.
  - FIELD_ACCESS
```
public static final SqlKind FIELD_ACCESS
```
    The field access operator, ".".
    (Only used at the RexNode level; at SqlNode level, a field-access is part of an identifier.)
  - INPUT_REF
```
public static final SqlKind INPUT_REF
```
    Reference to an input field.
    (Only used at the RexNode level.)
  - TABLE_INPUT_REF
```
public static final SqlKind TABLE_INPUT_REF
```
    Reference to an input field, with a qualified name and an identifier
    (Only used at the RexNode level.)
  - PATTERN_INPUT_REF
```
public static final SqlKind PATTERN_INPUT_REF
```
    Reference to an input field, with pattern var as modifier
    (Only used at the RexNode level.)
  - LOCAL_REF
```
public static final SqlKind LOCAL_REF
```
    Reference to a sub-expression computed within the current relational operator.
    (Only used at the RexNode level.)
  - CORREL_VARIABLE
```
public static final SqlKind CORREL_VARIABLE
```
    Reference to correlation variable.
    (Only used at the RexNode level.)
  - PATTERN_QUANTIFIER
```
public static final SqlKind PATTERN_QUANTIFIER
```
    the repetition quantifier of a pattern factor in a match_recognize clause.
  - ROW
```
public static final SqlKind ROW
```
    The row-constructor function. May be explicit or implicit: VALUES 1, ROW (2).
  - COLUMN_LIST
```
public static final SqlKind COLUMN_LIST
```
    The non-standard constructor used to pass a COLUMN_LIST parameter to a user-defined transform.
  - CAST
```
public static final SqlKind CAST
```
    The "CAST" operator.
  - NEXT_VALUE
```
public static final SqlKind NEXT_VALUE
```
    The "NEXT VALUE OF sequence" operator.
  - CURRENT_VALUE
```
public static final SqlKind CURRENT_VALUE
```
    The "CURRENT VALUE OF sequence" operator.
  - FLOOR
```
public static final SqlKind FLOOR
```
    The "FLOOR" function
  - CEIL
```
public static final SqlKind CEIL
```
    The "CEIL" function
  - TRIM
```
public static final SqlKind TRIM
```
    The "TRIM" function.
  - LTRIM
```
public static final SqlKind LTRIM
```
    The "LTRIM" function (Oracle).
  - RTRIM
```
public static final SqlKind RTRIM
```
    The "RTRIM" function (Oracle).
  - EXTRACT
```
public static final SqlKind EXTRACT
```
    The "EXTRACT" function.
  - JDBC_FN
```
public static final SqlKind JDBC_FN
```
    Call to a function using JDBC function syntax.
  - MULTISET_VALUE_CONSTRUCTOR
```
public static final SqlKind MULTISET_VALUE_CONSTRUCTOR
```
    The MULTISET value constructor.
  - MULTISET_QUERY_CONSTRUCTOR
```
public static final SqlKind MULTISET_QUERY_CONSTRUCTOR
```
    The MULTISET query constructor.
  - JSON_VALUE_EXPRESSION
```
public static final SqlKind JSON_VALUE_EXPRESSION
```
    The JSON value expression.
  - JSON_API_COMMON_SYNTAX
```
public static final SqlKind JSON_API_COMMON_SYNTAX
```
    The JSON API common syntax.
  - JSON_ARRAYAGG
```
public static final SqlKind JSON_ARRAYAGG
```
    The JSON_ARRAYAGG aggregate function.
  - JSON_OBJECTAGG
```
public static final SqlKind JSON_OBJECTAGG
```
    The JSON_OBJECTAGG aggregate function.
  - UNNEST
```
public static final SqlKind UNNEST
```
    The "UNNEST" operator.
  - LATERAL
```
public static final SqlKind LATERAL
```
    The "LATERAL" qualifier to relations in the FROM clause.
  - COLLECTION_TABLE
```
public static final SqlKind COLLECTION_TABLE
```
    Table operator which converts user-defined transform into a relation, for example, select * from TABLE(udx(x, y, z)). See also the EXPLICIT_TABLE prefix operator.
  - ARRAY_VALUE_CONSTRUCTOR
```
public static final SqlKind ARRAY_VALUE_CONSTRUCTOR
```
    Array Value Constructor, e.g. Array[1, 2, 3].
  - ARRAY_QUERY_CONSTRUCTOR
```
public static final SqlKind ARRAY_QUERY_CONSTRUCTOR
```
    Array Query Constructor, e.g. Array(select deptno from dept).
  - MAP_VALUE_CONSTRUCTOR
```
public static final SqlKind MAP_VALUE_CONSTRUCTOR
```
    Map Value Constructor, e.g. Map['washington', 1, 'obama', 44].
  - MAP_QUERY_CONSTRUCTOR
```
public static final SqlKind MAP_QUERY_CONSTRUCTOR
```
    Map Query Constructor, e.g. MAP (SELECT empno, deptno FROM emp).
  - CURSOR
```
public static final SqlKind CURSOR
```
    CURSOR constructor, for example, select * from TABLE(udx(CURSOR(select ...), x, y, z))
  - LITERAL_CHAIN
```
public static final SqlKind LITERAL_CHAIN
```
    Literal chain operator (for composite string literals). An internal operator that does not appear in SQL syntax.
  - ESCAPE
```
public static final SqlKind ESCAPE
```
    Escape operator (always part of LIKE or SIMILAR TO expression). An internal operator that does not appear in SQL syntax.
  - REINTERPRET
```
public static final SqlKind REINTERPRET
```
    The internal REINTERPRET operator (meaning a reinterpret cast). An internal operator that does not appear in SQL syntax.
  - EXTEND
```
public static final SqlKind EXTEND
```
    The internal EXTEND operator that qualifies a table name in the FROM clause.
  - CUBE
```
public static final SqlKind CUBE
```
    The internal CUBE operator that occurs within a GROUP BY clause.
  - ROLLUP
```
public static final SqlKind ROLLUP
```
    The internal ROLLUP operator that occurs within a GROUP BY clause.
  - GROUPING_SETS
```
public static final SqlKind GROUPING_SETS
```
    The internal GROUPING SETS operator that occurs within a GROUP BY clause.
  - GROUPING
```
public static final SqlKind GROUPING
```
    The GROUPING(e, ...) function.
  - GROUPING_ID
```
@Deprecated
public static final SqlKind GROUPING_ID
```
    Deprecated.
    Use GROUPING.
  - GROUP_ID
```
public static final SqlKind GROUP_ID
```
    The GROUP_ID() function.
  - PATTERN_PERMUTE
```
public static final SqlKind PATTERN_PERMUTE
```
    The internal "permute" function in a MATCH_RECOGNIZE clause.
  - PATTERN_EXCLUDED
```
public static final SqlKind PATTERN_EXCLUDED
```
    The special patterns to exclude enclosing pattern from output in a MATCH_RECOGNIZE clause.
  - COUNT
```
public static final SqlKind COUNT
```
    The COUNT aggregate function.
  - SUM
```
public static final SqlKind SUM
```
    The SUM aggregate function.
  - SUM0
```
public static final SqlKind SUM0
```
    The SUM0 aggregate function.
  - MIN
```
public static final SqlKind MIN
```
    The MIN aggregate function.
  - MAX
```
public static final SqlKind MAX
```
    The MAX aggregate function.
  - LEAD
```
public static final SqlKind LEAD
```
    The LEAD aggregate function.
  - LAG
```
public static final SqlKind LAG
```
    The LAG aggregate function.
  - FIRST_VALUE
```
public static final SqlKind FIRST_VALUE
```
    The FIRST_VALUE aggregate function.
  - LAST_VALUE
```
public static final SqlKind LAST_VALUE
```
    The LAST_VALUE aggregate function.
  - ANY_VALUE
```
public static final SqlKind ANY_VALUE
```
    The ANY_VALUE aggregate function.
  - COVAR_POP
```
public static final SqlKind COVAR_POP
```
    The COVAR_POP aggregate function.
  - COVAR_SAMP
```
public static final SqlKind COVAR_SAMP
```
    The COVAR_SAMP aggregate function.
  - REGR_COUNT
```
public static final SqlKind REGR_COUNT
```
    The REGR_COUNT aggregate function.
  - REGR_SXX
```
public static final SqlKind REGR_SXX
```
    The REGR_SXX aggregate function.
  - REGR_SYY
```
public static final SqlKind REGR_SYY
```
    The REGR_SYY aggregate function.
  - AVG
```
public static final SqlKind AVG
```
    The AVG aggregate function.
  - STDDEV_POP
```
public static final SqlKind STDDEV_POP
```
    The STDDEV_POP aggregate function.
  - STDDEV_SAMP
```
public static final SqlKind STDDEV_SAMP
```
    The STDDEV_SAMP aggregate function.
  - VAR_POP
```
public static final SqlKind VAR_POP
```
    The VAR_POP aggregate function.
  - VAR_SAMP
```
public static final SqlKind VAR_SAMP
```
    The VAR_SAMP aggregate function.
  - NTILE
```
public static final SqlKind NTILE
```
    The NTILE aggregate function.
  - NTH_VALUE
```
public static final SqlKind NTH_VALUE
```
    The NTH_VALUE aggregate function.
  - COLLECT
```
public static final SqlKind COLLECT
```
    The COLLECT aggregate function.
  - FUSION
```
public static final SqlKind FUSION
```
    The FUSION aggregate function.
  - SINGLE_VALUE
```
public static final SqlKind SINGLE_VALUE
```
    The SINGLE_VALUE aggregate function.
  - ROW_NUMBER
```
public static final SqlKind ROW_NUMBER
```
    The ROW_NUMBER window function.
  - RANK
```
public static final SqlKind RANK
```
    The RANK window function.
  - PERCENT_RANK
```
public static final SqlKind PERCENT_RANK
```
    The PERCENT_RANK window function.
  - DENSE_RANK
```
public static final SqlKind DENSE_RANK
```
    The DENSE_RANK window function.
  - CUME_DIST
```
public static final SqlKind CUME_DIST
```
    The ROW_NUMBER window function.
  - TUMBLE
```
public static final SqlKind TUMBLE
```
    The TUMBLE group function.
  - TUMBLE_START
```
public static final SqlKind TUMBLE_START
```
    The TUMBLE_START auxiliary function of the TUMBLE group function.
  - TUMBLE_END
```
public static final SqlKind TUMBLE_END
```
    The TUMBLE_END auxiliary function of the TUMBLE group function.
  - HOP
```
public static final SqlKind HOP
```
    The HOP group function.
  - HOP_START
```
public static final SqlKind HOP_START
```
    The HOP_START auxiliary function of the HOP group function.
  - HOP_END
```
public static final SqlKind HOP_END
```
    The HOP_END auxiliary function of the HOP group function.
  - SESSION
```
public static final SqlKind SESSION
```
    The SESSION group function.
  - SESSION_START
```
public static final SqlKind SESSION_START
```
    The SESSION_START auxiliary function of the SESSION group function.
  - SESSION_END
```
public static final SqlKind SESSION_END
```
    The SESSION_END auxiliary function of the SESSION group function.
  - COLUMN_DECL
```
public static final SqlKind COLUMN_DECL
```
    Column declaration.
  - ATTRIBUTE_DEF
```
public static final SqlKind ATTRIBUTE_DEF
```
    Attribute definition.
  - CHECK
```
public static final SqlKind CHECK
```
    CHECK constraint.
  - UNIQUE
```
public static final SqlKind UNIQUE
```
    UNIQUE constraint.
  - PRIMARY_KEY
```
public static final SqlKind PRIMARY_KEY
```
    PRIMARY KEY constraint.
  - FOREIGN_KEY
```
public static final SqlKind FOREIGN_KEY
```
    FOREIGN KEY constraint.
  - COMMIT
```
public static final SqlKind COMMIT
```
    COMMIT session control statement.
  - ROLLBACK
```
public static final SqlKind ROLLBACK
```
    ROLLBACK session control statement.
  - ALTER_SESSION
```
public static final SqlKind ALTER_SESSION
```
    ALTER SESSION DDL statement.
  - CREATE_SCHEMA
```
public static final SqlKind CREATE_SCHEMA
```
    CREATE SCHEMA DDL statement.
  - CREATE_FOREIGN_SCHEMA
```
public static final SqlKind CREATE_FOREIGN_SCHEMA
```
    CREATE FOREIGN SCHEMA DDL statement.
  - DROP_SCHEMA
```
public static final SqlKind DROP_SCHEMA
```
    DROP SCHEMA DDL statement.
  - CREATE_TABLE
```
public static final SqlKind CREATE_TABLE
```
    CREATE TABLE DDL statement.
  - ALTER_TABLE
```
public static final SqlKind ALTER_TABLE
```
    ALTER TABLE DDL statement.
  - DROP_TABLE
```
public static final SqlKind DROP_TABLE
```
    DROP TABLE DDL statement.
  - CREATE_VIEW
```
public static final SqlKind CREATE_VIEW
```
    CREATE VIEW DDL statement.
  - ALTER_VIEW
```
public static final SqlKind ALTER_VIEW
```
    ALTER VIEW DDL statement.
  - DROP_VIEW
```
public static final SqlKind DROP_VIEW
```
    DROP VIEW DDL statement.
  - CREATE_MATERIALIZED_VIEW
```
public static final SqlKind CREATE_MATERIALIZED_VIEW
```
    CREATE MATERIALIZED VIEW DDL statement.
  - ALTER_MATERIALIZED_VIEW
```
public static final SqlKind ALTER_MATERIALIZED_VIEW
```
    ALTER MATERIALIZED VIEW DDL statement.
  - DROP_MATERIALIZED_VIEW
```
public static final SqlKind DROP_MATERIALIZED_VIEW
```
    DROP MATERIALIZED VIEW DDL statement.
  - CREATE_SEQUENCE
```
public static final SqlKind CREATE_SEQUENCE
```
    CREATE SEQUENCE DDL statement.
  - ALTER_SEQUENCE
```
public static final SqlKind ALTER_SEQUENCE
```
    ALTER SEQUENCE DDL statement.
  - DROP_SEQUENCE
```
public static final SqlKind DROP_SEQUENCE
```
    DROP SEQUENCE DDL statement.
  - CREATE_INDEX
```
public static final SqlKind CREATE_INDEX
```
    CREATE INDEX DDL statement.
  - ALTER_INDEX
```
public static final SqlKind ALTER_INDEX
```
    ALTER INDEX DDL statement.
  - DROP_INDEX
```
public static final SqlKind DROP_INDEX
```
    DROP INDEX DDL statement.
  - CREATE_TYPE
```
public static final SqlKind CREATE_TYPE
```
    CREATE TYPE DDL statement.
  - DROP_TYPE
```
public static final SqlKind DROP_TYPE
```
    DROP TYPE DDL statement.
  - CREATE_FUNCTION
```
public static final SqlKind CREATE_FUNCTION
```
    CREATE FUNCTION DDL statement.
  - DROP_FUNCTION
```
public static final SqlKind DROP_FUNCTION
```
    DROP FUNCTION DDL statement.
  - OTHER_DDL
```
public static final SqlKind OTHER_DDL
```
    DDL statement not handled above.
    Note to other projects: If you are extending Calcite's SQL parser and have your own object types you no doubt want to define CREATE and DROP commands for them. Use OTHER_DDL in the short term, but we are happy to add new enum values for your object types. Just ask!
- Field Detail
  - SET_QUERY
```
public static final java.util.EnumSet<SqlKind> SET_QUERY
```
    Category consisting of set-query node types.
    Consists of: EXCEPT, INTERSECT, UNION.
  - AGGREGATE
```
public static final java.util.EnumSet<SqlKind> AGGREGATE
```
    Category consisting of all built-in aggregate functions.
  - DML
```
public static final java.util.EnumSet<SqlKind> DML
```
    Category consisting of all DML operators.
    Consists of: INSERT, UPDATE, DELETE, MERGE, PROCEDURE_CALL.
    NOTE jvs 1-June-2006: For now we treat procedure calls as DML; this makes it easy for JDBC clients to call execute or executeUpdate and not have to process dummy cursor results. If in the future we support procedures which return results sets, we'll need to refine this.
  - DDL
```
public static final java.util.EnumSet<SqlKind> DDL
```
    Category consisting of all DDL operators.
  - QUERY
```
public static final java.util.EnumSet<SqlKind> QUERY
```
    Category consisting of query node types.
    Consists of: SELECT, EXCEPT, INTERSECT, UNION, VALUES, ORDER_BY, EXPLICIT_TABLE.
  - EXPRESSION
```
public static final java.util.Set<SqlKind> EXPRESSION
```
    Category consisting of all expression operators.
    A node is an expression if it is NOT one of the following: AS, ARGUMENT_ASSIGNMENT, DEFAULT, DESCENDING, SELECT, JOIN, OTHER_FUNCTION, CAST, TRIM, LITERAL_CHAIN, JDBC_FN, PRECEDING, FOLLOWING, ORDER_BY, COLLECTION_TABLE, TABLESAMPLE, or an aggregate function, DML or DDL.
  - TOP_LEVEL
```
public static final java.util.EnumSet<SqlKind> TOP_LEVEL
```
    Category of all SQL statement types.
    Consists of all types in QUERY, DML and DDL.
  - FUNCTION
```
public static final java.util.Set<SqlKind> FUNCTION
```
    Category consisting of regular and special functions.
    Consists of regular functions OTHER_FUNCTION and special functions ROW, TRIM, CAST, JDBC_FN.
  - AVG_AGG_FUNCTIONS
```
public static final java.util.Set<SqlKind> AVG_AGG_FUNCTIONS
```
    Category of SqlAvgAggFunction.
    Consists of AVG, STDDEV_POP, STDDEV_SAMP, VAR_POP, VAR_SAMP.
  - COVAR_AVG_AGG_FUNCTIONS
```
public static final java.util.Set<SqlKind> COVAR_AVG_AGG_FUNCTIONS
```
    Category of SqlCovarAggFunction.
    Consists of COVAR_POP, COVAR_SAMP, REGR_SXX, REGR_SYY.
  - COMPARISON
```
public static final java.util.Set<SqlKind> COMPARISON
```
    Category of comparison operators.
    Consists of: IN, EQUALS, NOT_EQUALS, LESS_THAN, GREATER_THAN, LESS_THAN_OR_EQUAL, GREATER_THAN_OR_EQUAL.
  - lowerName
```
public final java.lang.String lowerName
```
    Lower-case name.
  - sql
```
public final java.lang.String sql
```
- Constructor Detail
  - SqlKind
```
private SqlKind()
```
  - SqlKind
```
private SqlKind(java.lang.String sql)
```
- Method Detail
  - values
```
public static SqlKind[] values()
```
    Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:
    for (SqlKind c : SqlKind.values()) System.out.println(c);
    Returns:
    
    an array containing the constants of this enum type, in the order they are declared
  - valueOf
```
public static SqlKind valueOf(java.lang.String name)
```
    Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)
    
    Parameters:
    
    name - the name of the enum constant to be returned.
    
    Returns:
    
    the enum constant with the specified name
    
    Throws:
    
    java.lang.IllegalArgumentException - if this enum type has no constant with the specified name
    
    java.lang.NullPointerException - if the argument is null
  - reverse
```
public SqlKind reverse()
```
    Returns the kind that corresponds to this operator but in the opposite direction. Or returns this, if this kind is not reversible.
    For example, GREATER_THAN.reverse() returns LESS_THAN.
  - negate
```
public SqlKind negate()
```
    Returns the kind that you get if you apply NOT to this kind.
    For example, IS_NOT_NULL.negate() returns IS_NULL.
    For IS_TRUE, IS_FALSE, IS_NOT_TRUE, IS_NOT_FALSE, nullable inputs need to be treated carefully.
    NOT(IS_TRUE(null)) = NOT(false) = true, while IS_FALSE(null) = false, so NOT(IS_TRUE(X)) should be IS_NOT_TRUE(X). On the other hand, IS_TRUE(NOT(null)) = IS_TRUE(null) = false.
    This is why negate() != negateNullSafe() for these operators.
  - negateNullSafe
```
public SqlKind negateNullSafe()
```
    Returns the kind that you get if you negate this kind. To conform to null semantics, null value should not be compared.
    For IS_TRUE, IS_FALSE, IS_NOT_TRUE and IS_NOT_FALSE, nullable inputs need to be treated carefully:
    
    NOT(IS_TRUE(null)) = NOT(false) = true
    IS_TRUE(NOT(null)) = IS_TRUE(null) = false
    IS_FALSE(null) = false
    IS_NOT_TRUE(null) = true
  - belongsTo
```
public final boolean belongsTo(java.util.Collection<SqlKind> category)
```
    Returns whether this SqlKind belongs to a given category.
    A category is a collection of kinds, not necessarily disjoint. For example, QUERY is { SELECT, UNION, INTERSECT, EXCEPT, VALUES, ORDER_BY, EXPLICIT_TABLE }.
    
    Parameters:
    
    category - Category
    
    Returns:
    
    Whether this kind belongs to the given category
  - concat
```
@SafeVarargs
private static <E extends java.lang.Enum<E>> java.util.EnumSet<E> concat(java.util.EnumSet<E> set0,
                                                                         java.util.EnumSet<E>... sets)
```

Modifier	Constructor	Description
`private`	`SqlKind()`
`private`	`SqlKind(java.lang.String sql)`

Enum SqlKind

Enum Constant Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Enum

Methods inherited from class java.lang.Object

Enum Constant Detail

OTHER

SELECT

JOIN

IDENTIFIER

LITERAL

OTHER_FUNCTION

EXPLAIN

DESCRIBE_SCHEMA

DESCRIBE_TABLE

INSERT

DELETE

UPDATE

SET_OPTION

DYNAMIC_PARAM

ORDER_BY

WITH

WITH_ITEM

UNION

EXCEPT

INTERSECT

AS

ARGUMENT_ASSIGNMENT

DEFAULT

OVER

FILTER

WITHIN_GROUP

WINDOW

MERGE

TABLESAMPLE

MATCH_RECOGNIZE

TIMES

DIVIDE

MOD

PLUS

MINUS

PATTERN_ALTER

PATTERN_CONCAT

IN

NOT_IN

LESS_THAN

GREATER_THAN

LESS_THAN_OR_EQUAL

GREATER_THAN_OR_EQUAL

EQUALS

NOT_EQUALS

IS_DISTINCT_FROM

IS_NOT_DISTINCT_FROM

OR

AND

DOT

OVERLAPS

CONTAINS

PRECEDES

IMMEDIATELY_PRECEDES

SUCCEEDS

IMMEDIATELY_SUCCEEDS

PERIOD_EQUALS

LIKE

SIMILAR

BETWEEN

CASE

NULLIF

COALESCE

DECODE

NVL

GREATEST

LEAST

TIMESTAMP_ADD

TIMESTAMP_DIFF

NOT

PLUS_PREFIX

MINUS_PREFIX