Shulou(Shulou.com)06/01 Report--

1 、 distinct

Select count (distinct CName) from tebleselect count (CName) from (select distinct CName from Course) as tempSELECT DISTINCT text_zhcn FROM dms_menuconfig-- to re-query the data in the table select DISTINCT (user_id) from user_info where children_merchant_id='kuaiditong'

2 、 group by

Select count (1) from Course group by CName

Document: mysql to re-query the data in the table. Note

Link: http://note.youdao.com/noteshare?id=581440d92396bab4de6568d1a69baa58&sub=9B8DAB091CC5490BA5F8FA29557CCD67

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