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  • 获取分组后取某字段最大一条记录(求每个类别中最大的值的列表)

    获取分组后取某字段最大一条记录
    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


    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

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  • 原文地址:https://www.cnblogs.com/firstdream/p/8808598.html
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