问几个sql语句
1.表A和表B,如何select AXB?
2.
table A (int KeyA),KeyA是A的key
table B(int KeyA,int value),KeyA是B的key
要求向B插入记录,条件是存在于A但不存在于B的KeyA,value值总是为0
[解决办法]
SELECT *FROM A,B
INSERT INTO B
SELECT KeyA,0 FROM A WHERE NOT EXISTS(SELECT *FROM B WHERE B.KeyA=A.KeyA)
[解决办法]
insert tb select Akey ,0 from ta where Akey not in (select Bkey from tb )
go
[解决办法]
---1、
Select * From A Cross Join B
---2、方法1
Insert Into B(KeyA,Value)
Select KeyA,0 From A Where Not Exists(Select 1 From B Where B.KeyA=A.KeyA)
---2、方法2
Insert B
Select KeyA,0 From A Where KeyA Not In(Select KeyA From B)
