IF

Synopsis

IF condition
  THEN statements
  [ ELSEIF condition THEN statements ]
  [ ... ]
  [ ELSE statements ]
END IF

Description

The IF THEN statement is an optional construct to allow conditional processing in SQL routines. Each condition following an IF or ELSEIF must evaluate to a boolean. The result of processing the expression must result in a boolean true value to process the statements in the THEN block. A result of false results in skipping the THEN block and moving to evaluate the next ELSEIF and ELSE blocks in order.

The ELSEIF and ELSE segments are optional.

Examples

FUNCTION simple_if(a bigint)
  RETURNS varchar
  BEGIN
    IF a = 0 THEN
      RETURN 'zero';
    ELSEIF a = 1 THEN
      RETURN 'one';
    ELSE
      RETURN 'more than one or negative';
    END IF;
  END

Further examples of varying complexity that cover usage of the IF statement in combination with other statements are available in the SQL routines examples documentation.

See also

• routines
• Conditional expressions using IF