SQL Reference

IF is a conditional statement in SQL that allows you to perform different actions based on whether a certain condition is true or false. It checks the condition first; if it evaluates to true, a certain statement or block of statements gets executed. If the condition evaluates to false, another set of statements are executed. This makes the control flow of SQL statements more flexible and dynamic.

Example

SET @input = 5;
SELECT IF(@input>3, 'Greater', 'Smaller') AS Result;

Output

+---------+
| Result  |
+---------+
| Greater |
+---------+

Explanation

In this example, the IF statement in SQL is used to compare a variable (@input) to a specific value. The IF statement checks if the value of @input is greater than 3. If the condition is true, it returns ‘Greater’. If the condition is false, it returns ‘Smaller’. The returned value is displayed as ‘Result’. In this case, since the value of @input is 5 which is indeed greater than 3, the output is ‘Greater’.

Example

DECLARE @Value INT;
SET @Value = 10;

IF (@Value > 5)
BEGIN
   PRINT 'Value is greater than 5';
END
ELSE
BEGIN
   PRINT 'Value is equal to or less than 5';
END

Output

Value is greater than 5

Explanation

In this example, an integer variable @Value is declared and set to 10. A conditional IF statement checks if the value is greater than 5. If the condition is true, it outputs Value is greater than 5. If it’s false, it would have output Value is equal to or less than 5. Since @Value was set to 10, the true condition was met resulting in the displayed output.

Example

DECLARE
    EMP_SALARY NUMBER(6) := 5500;
BEGIN
    IF EMP_SALARY > 8000 THEN
        DBMS_OUTPUT.PUT_LINE('High salary');
    ELSE
        DBMS_OUTPUT.PUT_LINE('Low salary');
    END IF;
END;
/

Output

Low salary

Explanation

In this example, a variable EMP_SALARY is declared and assigned a value of 5500. The IF statement checks whether the salary is greater than 8000. If the salary is above 8000, the string ‘High salary’ is output. Otherwise, ‘Low salary’ is output. As the set value of 5500 is less than 8000, the output is ‘Low salary’.