Logical Operators in PL/SQL


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Following table shows the Logical operators supported by PL/SQL. All these operators work on Boolean operands and produces Boolean results. Assume variable A holds true and variable B holds false, then −

Operator Description Examples
and Called the logical AND operator. If both the operands are true then condition becomes true. (A and B) is false.
or Called the logical OR Operator. If any of the two operands is true then condition becomes true. (A or B) is true.
not Called the logical NOT Operator. Used to reverse the logical state of its operand. If a condition is true then Logical NOT operator will make it false. not (A and B) is true.

Example

DECLARE 
   a boolean := true; 
   b boolean := false; 
BEGIN 
   IF (a AND b) THEN 
      dbms_output.put_line('Line 1 - Condition is true'); 
   END IF; 
   IF (a OR b) THEN 
      dbms_output.put_line('Line 2 - Condition is true'); 
   END IF; 
   IF (NOT a) THEN 
      dbms_output.put_line('Line 3 - a is not true'); 
   ELSE 
      dbms_output.put_line('Line 3 - a is true'); 
   END IF; 
   IF (NOT b) THEN 
      dbms_output.put_line('Line 4 - b is not true'); 
   ELSE 
      dbms_output.put_line('Line 4 - b is true'); 
   END IF; 
END; 
/ 

When the above code is executed at the SQL prompt, it produces the following result −

Line 2 - Condition is true 
Line 3 - a is true 
Line 4 - b is not true  

PL/SQL procedure successfully completed. 
plsql_operators.htm
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