DELIMITER //
CREATE PROCEDURE yourProcedureName(IN yourParameterName dataType,OUT
   yourParameterName dataType
)
BEGIN
yourStatement1;
yourStatement2;
.
.
N
END;
//
DELIMITER ;

mysql> create table SumOfAll
   -> (
   -> Amount int
   -> );
Query OK，0 rows affected (0.78 sec)

mysql> insert into SumOfAll values(100);
Query OK，1 row affected (0.18 sec)

mysql> insert into SumOfAll values(330);
Query OK，1 row affected (0.24 sec)

mysql> insert into SumOfAll values(450);
Query OK，1 row affected (0.10 sec)

mysql> insert into SumOfAll values(400);
Query OK，1 row affected (0.20 sec)

mysql> select *from SumOfAll;

+--------+
| Amount |
+--------+
| 100    |
| 330    |
| 450    |
| 400    |
+--------+
4 rows in set (0.00 sec)

mysql> DELIMITER //
mysql> create procedure sp_ChechValue(IN value1 int,OUT value2 int)
   -> begin
   -> set value2=(select Amount from SumOfAll where Amount=value1);
   -> end;
   -> //
Query OK，0 rows affected (0.20 sec)
mysql> delimiter ;

mysql> call sp_ChechValue(300,@isPresent);
Query OK，0 rows affected (0.00 sec)

mysql> select @isPresent;

+------------+
| @isPresent |
+------------+
| NULL       |
+------------+
1 row in set (0.00 sec)

mysql> call sp_ChechValue(330,@isPresent);
Query OK，0 rows affected (0.00 sec)

mysql> select @isPresent;

+------------+
| @isPresent |
+------------+
| 330        |
+------------+
1 row in set (0.00 sec)