DESCRIBE FUNCTION if;
DESCRIBE FUNCTION EXTENDED if;

EXPLAIN
SELECT IF(TRUE, 1, 2) AS COL1,
       IF(FALSE, CAST(NULL AS STRING), CAST(1 AS STRING)) AS COL2,
       IF(1=1, IF(2=2, 1, 2), IF(3=3, 3, 4)) AS COL3,
       IF(2=2, 1, NULL) AS COL4,
       IF(2=2, NULL, 1) AS COL5,
       IF(IF(TRUE, NULL, FALSE), 1, 2) AS COL6
FROM src LIMIT 1;


SELECT IF(TRUE, 1, 2) AS COL1,
       IF(FALSE, CAST(NULL AS STRING), CAST(1 AS STRING)) AS COL2,
       IF(1=1, IF(2=2, 1, 2), IF(3=3, 3, 4)) AS COL3,
       IF(2=2, 1, NULL) AS COL4,
       IF(2=2, NULL, 1) AS COL5,
       IF(IF(TRUE, NULL, FALSE), 1, 2) AS COL6
FROM src LIMIT 1;

-- Type conversions
EXPLAIN
SELECT IF(TRUE, CAST(128 AS SMALLINT), CAST(1 AS TINYINT)) AS COL1,
       IF(FALSE, 1, 1.1) AS COL2,
       IF(FALSE, 1, 'ABC') AS COL3,
       IF(FALSE, 'ABC', 12.3) AS COL4
FROM src LIMIT 1;

SELECT IF(TRUE, CAST(128 AS SMALLINT), CAST(1 AS TINYINT)) AS COL1,
       IF(FALSE, 1, 1.1) AS COL2,
       IF(FALSE, 1, 'ABC') AS COL3,
       IF(FALSE, 'ABC', 12.3) AS COL4
FROM src LIMIT 1;