PL/SQL - IF-THEN-ELSE Statement
A sequence of IF-THEN statements can be followed by an optional sequence of ELSE statements, which execute when the condition is FALSE.
Syntax for the IF-THEN-ELSE statement is:
IF condition THEN S1; ELSE S2; END IF;
Where, S1 and S2 are different sequence of statements. In the IF-THEN-ELSE statements, when the test condition is TRUE, the statement S1 is executed and S2 is skipped; when the test condition is FALSE, then S1 is bypassed and statement S2 is executed. For example:
IF color = red THEN dbms_output.put_line('You have chosen a red car') ELSE dbms_output.put_line('Please choose a color for your car'); END IF;
If the Boolean expression condition evaluates to true, then the if-then block of code will be executed otherwise the else block of code will be executed.
Let us try a complete example that would illustrate the concept:
DECLARE a number(3) := 100; BEGIN -- check the boolean condition using if statement IF( a < 20 ) THEN -- if condition is true then print the following dbms_output.put_line('a is less than 20 ' ); ELSE dbms_output.put_line('a is not less than 20 ' ); END IF; dbms_output.put_line('value of a is : ' || a); END; /
When the above code is executed at SQL prompt, it produces the following result:
a is not less than 20 value of a is : 100 PL/SQL procedure successfully completed.