MySQL Stored Procedure Return Value

To return a value from stored procedure, you need to use user defined session specific variable. Add @ symbol before variable name.

For example, use @symbol for variable valido. The syntax for the same is as follows:

SELECT @valido;

Whenever you use select statement, you need to use @anyVariableName. The syntax is as follows:

SELECT @anyVariableName;

Here is the demo of stored procedure of return value. The query to create a stored procedure is as follows:

mysql> create procedure ReturnValueFrom_StoredProcedure
   -> (
   -> In num1 int,
   -> In num2 int,
   -> out valido int
   -> )
   -> Begin
   ->    IF (num1> 4 and num2 > 5) THEN
   ->       SET valido = (num1+num2);
   ->    ELSE
   ->       SET valido = (num1-num2);
   ->    END IF;
   -> select @valido;
   -> end //
Query OK, 0 rows affected (0.32 sec)
mysql> DELIMITER ;

Call the stored procedure using CALL command. The query is as follows:

mysql> call ReturnValueFrom_StoredProcedure(10,6,@TotalSum);
+---------+
| @valido |
+---------+
| NULL    |
+---------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.01 sec)

Now check the result of stored procedure using select statement. The query is as follows:

mysql> select @TotalSum;

The following is the output:

+-----------+
| @TotalSum |
+-----------+
|        16 |
+-----------+
1 row in set (0.00 sec)

Now second call for difference of two values. Call the stored procedure.

mysql> call ReturnValueFrom_StoredProcedure(4,2,@TotalDiff);
+---------+
| @valido |
+---------+
| NULL    |
+---------+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.01 sec)

Check the result from user defined session-specific variable using select statement. The query is as follows:

mysql> select @TotalDiff;

The following is the output:

+------------+
| @TotalDiff |
+------------+
| 2          |
+------------+
1 row in set (0.00 sec)