select count(*) from (select distinct * from tablename)a
select count(distinct *) from s_sa
--语句有问题. select distinct count(*) from s_sa --是不是这样?? select 分组字段,count(*) from s_sa group by 分组字段
xeqtr1982(ShaKa),你好,想问你一下,“select count(*) from (select distinct * from tablename)a”这一句最后的那个a是什么意思啊?我也用过这个语句的了,就是没有在最后加a,运行时就报错的了
select count(*) from (select 分组字段 from s_sa group by 分组字段(是不希望重复的字段)) 即可 如: SELECT COUNT(*) FROM ( select UserID,SiteID from 表名 where UserID=317 GROUP BY UserID,SiteID) AS A
a是(select distinct * from tablename)这个结果集派生出来的表的别名
select distinct count(*) from s_sa --是不是这样??
select 分组字段,count(*) from s_sa
group by 分组字段
group by 分组字段(是不希望重复的字段)) 即可
如:
SELECT COUNT(*) FROM (
select UserID,SiteID from 表名 where UserID=317
GROUP BY UserID,SiteID) AS A