Sql语句distinct怎么用

[小毕同志]

select distinct(pclassname),id from Iproducts where pclassid between 21 and 28
查询pclassname的时候distinct起作用，但是加上ID就没有去除重复的。
那位大神帮我解决一下。

[__天涯寻梦]

你 id 难道不是主键，有重复的？

[bdmh]

select distinct pclassname,id from Iproducts where pclassid between 21 and 28
或者
select pclassname,id from Iproducts where pclassid between 21 and 28 group by pclassname,id

[熙风]

你这样写当然没去重复啊

select *, count(distinct pclassname) Iproducts where pclassid between 21 and 28 group by name

[cjh200102]

写法有问题

[qldsrx]

ID是主键的话，一放上去就没法去重复了。多个ID对应一个pclassname的话，你只能显示其中一个ID而不是全部显示，否则一行也变为多行了。

[熙风]

 select distinct pclassname,count(id)  Iproducts where pclassid between 21 and 28 group by name

[小毕同志]

ID就是主键有多个ID对应一个Pclassname