TABLE quotation
id clientid
1 25
2 25
3 25
4 25
5 26如何查询TABLE quotation中有多少个不同的客户端?我不希望重复的条目被计算多次。
我需要答案是2,在1行中,因为唯一不重复的条目是(25,26)。
发布于 2010-11-09 17:05:56
select count(distinct clientid) from quotation发布于 2010-11-09 17:09:01
我找到一条出路
SELECT COUNT(*) as total FROM (SELECT COUNT(*) FROM quotation GROUP BY
clientid) t1发布于 2012-11-29 01:28:10
如果您想要计算唯一条目的总数,这将在列计数中返回一个数字。
SELECT COUNT(*) as total FROM (SELECT COUNT(*) FROM quotation GROUP BY clientid having count(*) > 1) t1如果您想计算具有重复行的条目的总数,那么可以使用以下mysql。
SELECT COUNT(*) as total FROM (SELECT COUNT(*) FROM quotation GROUP BY clientid having count(*) >= 2) t1https://stackoverflow.com/questions/4131937
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