A WHERE clause is an optional part of a SelectExpression, DELETE statement, or UPDATE statement.
The WHERE clause lets you select rows based on a boolean expression. Only
rows for which the expression evaluates to TRUE are returned in the result,
or, in the case of a DELETE statement, deleted, or, in the case of an UPDATE
statement, updated.
Syntax WHERE Boolean expression WHERE
clauseSQL extensions toBoolean expressions
are allowed in the WHERE clause. Most of the general expressions listed in , can result in a
boolean value.
In addition, there are the more common boolean expressions.
Specific boolean operators listed in Table 10, take one or more operands;
the expressions return a boolean value.