分组依据中的第一行与最后一行 [英] 1st Row in Group By vs. Last Row

问题描述

想知道如何返回MySQL组中的第一行，而不是最后一行.返回一系列日期，但需要显示第一个日期.

Wondering how to return the 1st row in a MySQL group by vs. the last row. Returning a series of dates, but need the first one displayed.

select * from calendar where approved = 'pending' group by eventid; 

推荐答案

使用max的min功能insead返回组中的第一行与最后一行.

Use the min function insead of max to return the first row in a group vs the last row.

select min(date) from calendar ...

如果您希望每个组都有整行，请将表本身与每个组的最小日期进行过滤:

If you want the entire row for each group, join the table with itself filtered for the min dates on each group:

select c2.* from
    (select eventid, min(dt) dt from calendar
        where approved = 'pending' group by eventid) c1
inner join calendar c2 on c1.eventid=c2.eventid and c1.dt=c2.dt
group by eventid;

演示: http://www.sqlize.com/6lOr55p67c

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