MYSQL GROUP BY ORDER BY 分組排序獲取第一條數據

mysql 排序語句的寫法，網上真是林林總總，但能用的不多。甚至有很多寫法，從語法上看，就根本沒有排序的樣子。

求人不如求己，自己來吧。

有兩種寫法：

1.根據需要調整正序還是倒序

select * from tabnamexxxx t 
where t.id=(select id from tabnamexxxx t2 where t2.com = t.com order by t2.updatetime desc limit 1)
and t.com in ('xxxx','xxxxx')
GROUP BY t.com ;

2.更加的簡單粗暴，如果是少量的數據，直接單條數據查詢，然後 union all，適合工具一次性查詢，肯定是不適合在項目中用的，會被領導打死的（此爲免責聲明）。

select * from 
 (select  * from tablexxxxxx t where t.com = 'xxxxxx' order by t.updatetime desc limit 1) t 
 
 union all 
 
select * from 
 (select  * from tablexxxxxx t where t.com = 'xxxxxx' order by t.updatetime desc limit 1) t 
 
 union all 
 
select * from 
 (select  * from tablexxxxxx t where t.com = 'xxxxxx' order by t.updatetime desc limit 1) t 
 
 union all 
 
select * from 
 (select  * from tablexxxxxx t where t.com = 'xxxxxx' order by t.updatetime desc limit 1) t ;