mysql技巧--按某一欄位分組取最大(小)值所在行的資料，這是mysql資料庫程式設計師經常用到的在處理一些報表資料時候可以活用！那麼獵微網將總結幾種mysql查詢最大值 mysql查詢最小值的方法！

mysql表圖如下

具體Php 連線mysql資料庫php程式碼我就不寫 下面看select怎麼查詢

一、按name分組取val最大的值所在行的資料。

--方法1：
select a.* from tb a where val = (select max(val) from tb where name = a.name) order by a.name
--方法2：
select a.* from tb a where not exists(select 1 from tb where name = a.name and val > a.val)
--方法3：
select a.* from tb a,(select name,max(val) val from tb group by name) b where a.name = b.name and a.val = b.val order by a.name
--方法4：
select a.* from tb a inner join (select name , max(val) val from tb group by name) b on a.name = b.name and a.val = b.val order by a.name
--方法5
select a.* from tb a where 1 > (select count(*) from tb where name = a.name and val > a.val ) order by a.name
/*
name       val         memo
---------- ----------- --------------------
a          3           a3:a的第三個值
b          5           b5b5b5b5b5
*/
 

--方法1：
select a.* from tb a where val = (select min(val) from tb where name = a.name) order by a.name
--方法2：
select a.* from tb a where not exists(select 1 from tb where name = a.name and val < a.val)
--方法3：
select a.* from tb a,(select name,min(val) val from tb group by name) b where a.name = b.name and a.val = b.val order by a.name
--方法4：
select a.* from tb a inner join (select name , min(val) val from tb group by name) b on a.name = b.name and a.val = b.val order by a.name
--方法5
select a.* from tb a where 1 > (select count(*) from tb where name = a.name and val < a.val) order by a.name
/*
name       val         memo
---------- ----------- --------------------
a          1           a1--a的第一個值
b          1           b1--b的第一個值
*/