按列名从mysql表中获取最新记录

Question

我需要从下表中获取每个指标名称的最新记录，例如2015-11-16的数据GI和2015-11-14的GO。

我怎样才能做到这一点？

由于

Answer 1

有很多方法可以实现这一目标，称为group wise maximum https://dev.mysql.com/doc/refman/5.7/en/example-maximum-column-group-row.html

select t1.* from table_name t1
join (
 select indicator_name,max(indicator_date) as indicator_date from table_name
 group by indicator_name
)t2
on t1.indicator_name = t2.indicator_name 
and t1.indicator_date = t2.indicator_date

Answer 2

如果您想要每个indicator_name的最新行，那么您可以按indicator_name为每个行组分配一个行号，并按indicator_date按降序排序。

<强>查询

select t1.indicator_id, 
       t1.indicator_name, 
       t1.indicator_value, 
       t1.indicator_date
from 
(
     select indicator_id, 
            indicator_name, 
            indicator_value, 
            indicator_date, 
    (
        case indicator_name when @curA 
        then @curRow := @curRow + 1 
        else @curRow := 1 and @curA := indicator_name end 
    ) + 1 as rn 
    from tblIndicators t, 
    (select @curRow := 0, @curA := '') r 
    order by indicator_name,indicator_date desc 
)t1 
where t1.rn = 1;

SQL Fiddle

Answer 3

SELECT * from yourtable
GROUP BY indicator_name
ORDER BY indicator_date DESC

Answer 4

试试这个......

SELECT * FROM table_name ORDER BY indicator_name,indicator_date DESC