zoukankan      html  css  js  c++  java
  • SQL 分组后获取其中一个字段最大值的整条记录

    方法一:(效率最高)
    select * from test as a 
    where typeindex = (select max(b.typeindex) 
    from test as b 
    where a.type = b.type );


    方法二:(效率次之)
    select 
    a.* from test a,
    (select type,max(typeindex) typeindex from test group by type) b 
    where a.type = b.type and a.typeindex = b.typeindex order by a.type 



    方法三:
    select a.* from test a inner join (select type , max(typeindex) typeindex from test group by type) b on a.type = b.type and a.typeindex = b.typeindex order by a.type

    SELECT *
    FROM(SELECT MAX(lastUpdate) AS max_time FROM omp_assistexternal_dispatch GROUP BY workOrderId) t
    INNER JOIN omp_assistexternal_dispatch d on d.lastUpdate =t.max_time



    方法四:(效率最低)
    select * from
    (
    select *,ROW_NUMBER() OVER(PARTITION BY type ORDER BY typeindex DESC) as num
    from test
    ) t
    where t.num = 1

  • 相关阅读:
    作业十一
    作业十
    作业九
    作业八
    作业七
    作业六
    作业五
    作业四
    eclipse+maven+web服务,实现对hdfs的目录浏览展示
    Eclipse+hadoop伪态式分布+API
  • 原文地址:https://www.cnblogs.com/MIUMIUBLING/p/11903994.html
Copyright © 2011-2022 走看看