Question

我在MySQL中为借记操作创建了一个存储过程，如下所示：

-- --------------------------------------------------------------------------------
-- Routine DDL
-- Note: comments before and after the routine body will not be stored by the server
-- --------------------------------------------------------------------------------
DELIMITER $$

CREATE DEFINER=`root`@`localhost` PROCEDURE `debit`(IN snnno INT, IN amt INT, OUT bal INT, OUT msg VARCHAR(50))
BEGIN
       DECLARE cid INT;
       DECLARE actno INT;
       DECLARE existbal INT;
       SELECT customerid INTO cid FROM customer WHERE ssn=@ssnno;
       SELECT accountno INTO actno FROM customeraccounts WHERE customerid=@cid;
       SELECT balance INTO existbal FROM account WHERE accountno=@actno;
       IF @exisbal < @amt THEN
              SET msg = 'You dont have suficient balance';
       ELSE
              UPDATE account SET account.balance = account.balance - amt WHERE account.accountno = @actno; 
              INSERT INTO transactions VALUES(NULL, @actno, 'debit', amt);
              SELECT balance INTO bal FROM account WHERE account.accountno = @actno; 
       END IF;
END $$

表格如下：

mysql> select * from customeraccounts;
+------------+-----------+-------------------+
| customerid | accountno | accounttype       |
+------------+-----------+-------------------+
|          1 |       101 | Savings           |
|          2 |       102 | Savings           |
|          3 |       103 | Current           |
|          4 |       104 | Fixed Deposit     |
|          5 |       105 | Recurring Deposit |
+------------+-----------+-------------------+
5 rows in set (0.00 sec)

mysql> select * from customer;
+------------+--------------+------------------+--------------+------+
| customerid | customername | customerstreet   | customercity | ssn  |
+------------+--------------+------------------+--------------+------+
|          1 | Amy          | Ping Ting Road   | Hong Kong    | 2532 |
|          2 | Bob          | Texaco Road      | Hong Kong    | 8073 |
|          3 | Carson       | Deerfoot Trail   | Calgary      | 6667 |
|          4 | David        | University Drive | Calgary      | 4724 |
|          5 | John         | Ogden Road       | Calgary      | 3880 |
+------------+--------------+------------------+--------------+------+
5 rows in set (0.00 sec)

mysql> select * from account;
+-----------+---------+-------------+
| accountno | balance | credit_card |
+-----------+---------+-------------+
|       101 |     700 |        2000 |
|       102 |    2500 |        1000 |
|       103 |    2700 |        1200 |
|       104 |    4000 |        2500 |
|       105 |    4500 |        NULL |
+-----------+---------+-------------+
5 rows in set (0.00 sec)

现在，当我使用ssnno = 2532和amt = 100的输入执行存储过程时，我得到SQL错误，因为列'accountno'不能为空。

当我提到时，出现此错误的原因必须是该列必须声明为NOT NULL。所以我也改变了。

mysql> desc account;
+-------------+---------+------+-----+---------+-------+
| Field       | Type    | Null | Key | Default | Extra |
+-------------+---------+------+-----+---------+-------+
| accountno   | int(11) | NO   | PRI | NULL    |       |
| balance     | int(11) | NO   |     | NULL    |       |
| credit_card | int(11) | YES  |     | NULL    |       |
+-------------+---------+------+-----+---------+-------+
3 rows in set (0.01 sec)

这是什么问题？我不能得到它？我的手术是否正确？

Answer 1

得到了答案。我没有初始化变量。这是更新的程序：

-- --------------------------------------------------------------------------------
-- Routine DDL
-- Note: comments before and after the routine body will not be stored by the server
-- --------------------------------------------------------------------------------
DELIMITER $$

CREATE DEFINER=`root`@`localhost` PROCEDURE `debit`(IN ssnno INT, IN amt INT, OUT bal INT, OUT msg VARCHAR(45))
BEGIN
        DECLARE actno INT DEFAULT 0;
        DECLARE cid INT DEFAULT 0;
        DECLARE currentbal INT DEFAULT 0;
        SELECT customerid INTO cid FROM customer WHERE ssn = ssnno;
        SELECT accountno INTO actno FROM customeraccounts WHERE customerid = cid;
        SELECT balance INTO currentbal FROM account WHERE accountno = actno;
        IF currentbal > amt THEN 
        UPDATE account SET account.balance = account.balance - amt WHERE account.accountno = actno; 
        INSERT INTO transactions VALUES(NULL, actno, 'debit', amt);
        SELECT balance INTO bal FROM account WHERE account.accountno = actno; 
        SET msg = 'Successfully Debited';
        ELSE 
            SET msg = 'No Sufficient Balance';
            SET bal = currentbal;
        END IF;
END

MySQL存储过程执行错误

1 个答案: