PL/SQL - IF-THEN-ELSE Statement


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A sequence of IF-THEN statements can be followed by an optional sequence of ELSE statements, which execute when the condition is FALSE.

Syntax

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.

Flow Diagram

PL/SQL if-then-else statement

Example

Let us try an example that will help you understand 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 the SQL prompt, it produces the following result −

a is not less than 20 
value of a is : 100  

PL/SQL procedure successfully completed. 

plsql_conditional_control.htm


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