Conditional Statements

Conditional Statements

Conditional Control statements execute code only if a condition holds true. These statements allow different actions to be taken based on different conditions. The condition can range from a literal or variable to a function that returns a value.

MySQL supports two conditional control statements IF and CASE. Both provide similar functionality and the choice between the two is a matter of personal preference, However, we will discuss situations in which choosing one type of statement may be better than the other.

IF Statement

The structure of MySQL IF statement is very similar to one used in other programming languages.There are three different forms of the IF statement depending on how many conditions are being tested.

A single IF-THEN block is used if some statements are to be executed based on a specific condition. In the case of MySQL, a condition can evaluate to TRUE, FALSE, or NULL (neither true nor false). So unlike other programming languages if a condition is not TRUE it does not automatically mean that it is FALSE. The condition to execute the code is given between the IF and THEN words. If the condition holds true then statements written between the IF-THEN and END IF are executed otherwise the control moves to the next statement after the IF block. Multiple statements can be written in a block including calls to stored procedures, SET statements, loops and nested IFs.

IF Condition THEN

If_statements;

END IF;

The second variation of IF statement is used when we want to execute some statements when the condition for IF block ...