mysql - 无法在 MySQL 中使用有效参数调用过程

Question

我编写了一个 PL/SQL block ，它需要执行以下任务:

已创建 2 个表:

1) 借款人:

+-------------+-------------+------+-----+---------+-------+
| Field       | Type        | Null | Key | Default | Extra |
+-------------+-------------+------+-----+---------+-------+
| rollno      | int(11)     | NO   | PRI | NULL    |       |
| name        | varchar(30) | YES  |     | NULL    |       |
| dataofissue | date        | YES  |     | NULL    |       |
| nameofbook  | varchar(20) | YES  |     | NULL    |       |
| status      | varchar(2)  | YES  |     | NULL    |       |
+-------------+-------------+------+-----+---------+-------+

它的内容是:

+--------+------+-------------+------------+--------+
| rollno | name | dataofissue | nameofbook | status |
+--------+------+-------------+------------+--------+
|      1 | a    | 2018-09-10  | Ba         | I      |
|      2 | b    | 2018-09-10  | Bb         | I      |
|      3 | c    | 2018-09-01  | Cc         | R      |
|      4 | d    | 2018-08-01  | Dd         | I      |
|      5 | e    | 2018-09-21  | Ee         | I      |
|      6 | f    | 2018-09-18  | Ff         | I      |
+--------+------+-------------+------------+--------+

2) 很好 - 它没有数据。但是，它的模式是:

+--------+---------+------+-----+---------+-------+
| Field  | Type    | Null | Key | Default | Extra |
+--------+---------+------+-----+---------+-------+
| rollno | int(11) | NO   | PRI | NULL    |       |
| days   | int(11) | NO   |     | NULL    |       |
| amt    | int(11) | NO   |     | NULL    |       |
+--------+---------+------+-----+---------+-------+

检查编号。 Borrower 表中的天数(从发行日期到当前日期):

• 如果天数在 15 到 30 之间，则罚款金额为 5 美元/天。
• 如果没有。 天>30，则罚款金额为50 美元/天，少于 30 天的罚款为 5 美元/天。

然后，状态将从I变为R。 只有状态为 I 而不是 R 的人才会被罚款。

• I 表示已发行图书。
• R 表示还书。

Fine表中会存储相关信息，amt为罚款总额，date为还书时的curdate()。

这是我编写的过程，但我无法使用有效参数调用该过程。

mysql> Delimiter //
mysql> Create  procedure proce(in roll int, in bname varchar(20))
    -> Begin
    -> Declare notfound int default 0;
    -> Declare rno int default 0;
    -> Declare name varchar(20);
    -> Declare doi date;
    -> Declare nob varchar(20);
    -> Declare stat varchar(20);
    -> Declare diff int default 0;
    -> Declare fine  int default 0;
    -> Declare cursor_name cursor for select rollno, name, dataofissue, nameofbook, status from borrower;
    -> Declare continue handler for NOT FOUND set notfound=1;
    -> Open cursor_name;
    -> loop_1 : LOOP
    -> fetch cursor_name into rno, name, doi, nob, stat ;
    -> If notfound=1 then
    -> leave loop_1;
    -> end if;
    -> 
    -> If(rno=roll and nob=bname) then
    -> 
    -> Select datediff(curdate(),doi) as DAYS into diff;
    -> if(stat=“I”) then
    -> if(diff >=15  and diff <=30 ) then
    -> set fine=( diff-15 )*5;
    -> elseif( diff > 30 ) then 
    -> set fine=(diff-30)*50 + 15*5;
    -> end if;
    -> insert into fine values(rno,diff,fine);
    -> update borrower set status='D' where rollno=rno; 
    -> end if;
    -> 
    -> 
    -> End if;
    -> 
    -> End LOOP loop_1;
    -> Close cursor_name;
    -> End;//
Query OK, 0 rows affected (0.03 sec)

我在这里称它为:

mysql> call proce(1,"Ba")//

ERROR 1054 (42S22): Unknown column '“I”' in 'field list'

Answer 1

这个语句 if(stat=“I”) 中的奇数引号似乎是问题所在 - 更改为单引号并且 proc 工作。

如果存在 border 则删除表，fine; 创建表借款人( 滚动号 int(11) , 名称 varchar(30)， 发行日期数据，
nameofbook varchar(20), 状态变量(2)
); 插入借款人的值(value)观 ( 1 , 'a' , '2018-09-10' , 'Ba' , 'I'),
( 2 , 'b' , '2018-09-10' , 'Bb' , 'I'),
( 3 , 'c' , '2018-09-01' , 'Cc' , 'R'),
( 4 , 'd' , '2018-08-01' , 'Dd' , 'I'),
( 5 , 'e' , '2018-09-21' , 'Ee' , 'I'),
( 6 , 'f' , '2018-09-18' , 'Ff' , 'I');

create table fine
( rollno  int(11),
 days    int(11), 
 amt     int(11));

drop procedure if exists proce;
 Delimiter //
 Create  procedure proce(in roll int, in bname varchar(20))
     Begin
     Declare notfound int default 0;
     Declare rno int default 0;
     Declare name varchar(20);
     Declare doi date;
     Declare nob varchar(20);
     Declare stat varchar(20);
     Declare diff int default 0;
     Declare fine  int default 0;
     Declare cursor_name cursor for select rollno, name, dataofissue, nameofbook, status from borrower;
     Declare continue handler for NOT FOUND set notfound=1;
     Open cursor_name;
     loop_1 : LOOP
     fetch cursor_name into rno, name, doi, nob, stat ;
     If notfound=1 then
     leave loop_1;
     end if;

     If(rno=roll and nob=bname) then

     Select datediff(curdate(),doi) as DAYS into diff;

      if(stat='I') then
        if(diff >=15  and diff <=30 ) then
            set fine=( diff-15 )*5;
        elseif( diff > 30 ) then 
        set fine=(diff-30)*50 + 15*5;
        end if;
     insert into fine values(rno,diff,fine);
     update borrower set status='D' where rollno=rno; 
     end if;


     End if;


     End LOOP loop_1;
     Close cursor_name;
     End //

call proce(1,'Ba');

select * from fine;

+--------+------+------+
| rollno | days | amt  |
+--------+------+------+
|      1 |   42 |  675 |
+--------+------+------+
1 row in set (0.00 sec)

我还会检查列、声明的变量和参数是否具有相同的名称和反引号状态。