問(wèn)題描述

數(shù)據(jù)如下：

============================== usertimenum------------------------------ a 1479101865 3------------------------------ b 1479101866 2------------------------------ a 1479101866 1------------------------------ a 1479101867 5------------------------------ b 1479101868 1------------------------------ c 1479101868 7==============================

請(qǐng)問(wèn)以時(shí)間為單位，如何查每個(gè)用戶(hù)第一次記錄的num？

問(wèn)題解答

按時(shí)間順序排序后分組查詢(xún)

select user,num from (select * from tb order by time asc) as a group by a.user;