1、distinct
select count(distinct CName) from tebleselect count(CName) from (select distinct CName from Course) as temp SELECT DISTINCT text_zhcn FROM dms_menuconfig -- 去重查询表中数据
2、group by
select count(1) from Course group by CName
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1、distinct
select count(distinct CName) from tebleselect count(CName) from (select distinct CName from Course) as temp SELECT DISTINCT text_zhcn FROM dms_menuconfig -- 去重查询表中数据
2、group by
select count(1) from Course group by CName
转载于:https://www.cnblogs.com/lu2527/p/10824847.html