PL/SQL If Statement

PL/SQL supports the programming language features like conditional statements and iterative statements. PL/SQL IF statement check condition and transfer the execution flow on that matched block depending on a condition. IF statement execute or skip a sequence of one or more statements. PL/SQL IF statement four different type,

1. IF THEN Statement
2. IF THEN ELSE Statement
3. IF THEN ELSIF Statement
4. Nested IF THEN ELSE Statement

IF-THEN statement:

IF THEN Statement Syntax:

IF condition   
THEN   
Statement: {It is executed when condition is true}  
END IF;  

This syntax is used when you want to execute statements only when condition is TRUE.

For Example,

DECLARE
   no INTEGER(2) := 14;BEGIN
   IF ( no = 14 ) THEN
      DBMS_OUTPUT.PUT_LINE('condition true');   
   END IF;
END;
/

Result

condition true

PL/SQL procedure successfully completed.

IF-THEN-ELSE statement:

IF-THEN-ELSE statement Syntax:

IF condition   
THEN  
   {...statements to execute when condition is TRUE...}  
ELSE  
   {...statements to execute when condition is FALSE...}  
END IF; 

Example,

DECLARE
   no INTEGER(2) := 14;
BEGIN
   IF ( no = 11 ) THEN
      DBMS_OUTPUT.PUT_LINE(no || ' is same');   
   ELSE
      DBMS_OUTPUT.PUT_LINE(no || ' is not same');
   END IF;
END;
/

Result:

14 is not same

PL/SQL procedure successfully completed.

IF-THEN-ELSIF statement:

IF-THEN-ELSIF statement Syntax: 

IF condition1   
THEN  
   {...statements to execute when condition1 is TRUE...}  
ELSIF condition2   
THEN  
   {...statements to execute when condition2 is TRUE...}  
END IF;  

Example:

DECLARE
   result CHAR(20) := 'second';
BEGIN
   IF ( result = 'distinction' ) THEN
      DBMS_OUTPUT.PUT_LINE('First Class with Distinction');   
   ELSIF ( result = 'first' ) THEN
      DBMS_OUTPUT.PUT_LINE('First Class');  
   ELSIF ( result = 'second' ) THEN
      DBMS_OUTPUT.PUT_LINE('Second Class');  
   ELSIF ( result = 'third' ) THEN
      DBMS_OUTPUT.PUT_LINE('Third Class');        
   ELSE
      DBMS_OUTPUT.PUT_LINE('Fail');
   END IF;
END;
/

Result

Second Class

PL/SQL procedure successfully completed.

Nested IF THEN ELSE Statement:

Nested IF THEN ELSE Statement Syntax: 

IF condition1   
THEN  
   {...statements to execute when condition1 is TRUE...}  
ELSIF condition2   
THEN  
   {...statements to execute when condition2 is TRUE...}  
ELSE  
   {...statements to execute when both condition1 and condition2 are FALSE...}  
END IF;  

For Example,

DECLARE
    gender CHAR(20) := 'female';
    result CHAR(20) := 'second';
BEGIN
   IF ( gender = 'male' ) THEN
      DBMS_OUTPUT.PUT_LINE('Gender Male Record Skip!');  
   ELSE 
       IF ( result = 'distinction' ) THEN
          DBMS_OUTPUT.PUT_LINE('First Class with Distinction');   
       ELSIF ( result = 'first' ) THEN
          DBMS_OUTPUT.PUT_LINE('First Class');  
       ELSIF ( result = 'second' ) THEN
          DBMS_OUTPUT.PUT_LINE('Second Class');  
       ELSIF ( result = 'third' ) THEN
          DBMS_OUTPUT.PUT_LINE('Third Class');        
       ELSE
          DBMS_OUTPUT.PUT_LINE('Fail');
       END IF;
    END IF;
END;
/

Result

Second Class

PL/SQL procedure successfully completed.