Question

SQL 判断重复值

表tb1
id firstName LastName sameNmaeFlag
100 wang ping
101 li lei
103 li lei 103
若插入数据时，此记录的 firstName 和LastName 已有相同的记录，则在此条记录sameNameFlag字段插入id号，没记录sameNameFlag为空。。
id firstName LastName sameNmaeFlag
100 wang ping
101 li lei
103 li lei 103
如何插入新的记录（SQL)

Answer 1

insert into table1(id,firstname,lastname,samenameflag) select
newid,newfirstname,newlastname,samenameflag from
(select case when count(*)>0 then newid else '' end as samenameflag from table1 where firstname=newfirstname and lastname=newlastname ) tmp

newid等就是你插入的固定值

Answer 2

ID是手动插入还是自增的？
做个触发器吧
create tb1_insert
on tb1
after insert
as
begin
declare @id int,@firstName varchar(50),@LastName varchar(50),@qty int
select @id=id,@LastName=LastName,@firstName=firstName from inserted
select @qty=count(*) from tb1 where LastName=@LastName and firstName=@firstName
if @qty>1
update tb1 set sameNmaeFlag=@id where id=@id
end

Answer 3

触发器写的不错.顶一个