PL/SQL - Basic Syntax
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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 | Example |
|---|---|---|
| and | Called logical AND operator. If both the operands are true then condition becomes true. | (A and B) is false. |
| or | Called logical OR Operator. If any of the two operands is true then condition becomes true. | (A or B) is true. |
| not | Called 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 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.