一题目,求多方法
- SQL code
create table T( id int,name varchar(4))insert into T values(1,'A'),(1,'B'),(2,'A'),(2,'C'),(3,'C');--选出name有A无B的id号--方法一:select * from (select * from T where name='A')as a where ID<>(select id from T where name='B')
还有别的方法来实现吗?
[解决办法]
SELECT * FTOM T T1
WHERE NOT EXISTS(SELECT 1 FROM T WHERE ID=T1.ID AND NAME<>T1.NAME AND NAME='B')
and t1.name='a'
[解决办法]
select t1.* from T as t1
inner join T t2 on (t1.id = t2.id and t1.name <> t2.name)
and t2.name <> 'B'
where t1.name = 'A'
[解决办法]
- SQL code
create table T( id int,name varchar(4))insert into T values(1,'A'),(1,'B'),(2,'A'),(2,'C'),(3,'C');select t1.*from T t1where t1.name='A' and not exists(select 1 from T t2 where t2.id=t1.id and t2.name='B')/*id name----------- ----2 A(1 row(s) affected)*/
[解决办法]
- SQL code
SELECT *FROM t AS aWHERE NAME = 'a' AND NOT EXISTS ( SELECT 1 FROM t WHERE id = a.id AND NAME = 'b' )