如何写一条插入语句,在插入的时候先判断是否和表里的数据重复 - 编程论坛

#2

jyxy2007-06-06 02:50

以下是引用comebaby在2007-6-5 22:20:40的发言：

例如:
grade class id name english math chinese
1 501 50101 dsfe 80 90 40
2 501 50101 dsfe 80 70 60

能不能先设置primary key,会简单一些.

#3

comebaby2007-06-06 03:28

不能设``因为我要用VC对它操作的`
如果设的话``一些重复就不行了``
我只要实现该功能的SQL语句

#4

songyang2012007-06-06 10:12

if not exists(select * from aaa where aa='a' and bb='b' and cc='c' )
insert into aaa values('a','b','c')

#5

comebaby2007-06-06 13:12

这是我在数据库的定义
grade int 4 0
class char 50 0
id char 50 0
name char 50 0
english float 8 0
math float 8 0
chinese float 8 0
summark float 8 1(允许为空)
average float 8 1(允许为空)

执行语句:
IF NOT EXISTS (SELECT *
FROM student
WHERE grade = 1 AND class = '503' AND id = '50333' AND
name = 'kkkk' AND english = 60 AND math = 70 AND chinese = 80)
INSERT
INTO student
VALUES (1, '503', '50333', 'kkkk', 60, 70, 80)

出错:查询计算器不支持IF SQL构造
出错:插入出错:列名或所提供值的数目与表定义不匹配

#6

songyang2012007-06-06 14:17

你插入的VALUES (1, '503', '50333', 'kkkk', 60, 70, 80)中缺少summark和average的数值。

#7

comebaby2007-06-07 10:48

``谢谢``