PostgreSQL – IF Statement

PostgreSQL has an IF statement executes `statements` if a condition is true. If the condition evaluates to false, the control is passed to the next statement after the END IF part.

Syntax:
IF condition THEN
   statements;
END IF;

The above conditional statement is a boolean expression that evaluates to either true or false.

Example 1:

In this example, we declare two variables a and b. In the body of the block, we compare the value of a and b using the comparison operator >, < and = in the boolean expressions of the IF statements.

DO $$
DECLARE
  a integer := 10;
  b integer := 20;
BEGIN 
  IF a > b THEN
    RAISE NOTICE 'a is greater than b';
  END IF;

  IF a < b THEN
    RAISE NOTICE 'a is less than b';
  END IF;

  IF a = b THEN
    RAISE NOTICE 'a is equal to b';
  END IF;
END $$;

Output:

Example 2:

DO $$
DECLARE
   a integer := 10;
   b integer := 10;
BEGIN 
  IF a > b THEN 
     RAISE NOTICE 'a is greater than b';
  ELSIF a < b THEN
     RAISE NOTICE 'a is less than b';
  ELSE
     RAISE NOTICE 'a is equal to b';
  END IF;
END $$;

Output: