如何从联盟表中获得前1名

Question

我正在获取重复记录。我想知道如何以最高的＆＃34; docdate-最后收到的日期＆＃34;任何人都可以指出我正确的方向。我是sql查询的新手。我正在使用MS sql sever 2016。

(
        select a.vendorid,
            max(a.DOCDATE) as [Last Date Received],
            max(b.VENDNAME) as [Vendor Name] --, b.VNDCLSID
            --  ,a.* 
        from PM20000 a
        inner join PM00200 b on a.VENDORID = b.VENDORID
        where b.VNDCLSID in ('cb', '6')
        group by a.VENDORID
        )

union

(
    select a.VENDORID,
        max(a.DOCDATE) as [Last Date Received],
        max(b.VENDNAME) as [Vendor Name] --, b.VNDCLSID
        --,a.* 
    from PM30200 a
    inner join PM00200 b on a.VENDORID = b.VENDORID
    where b.VNDCLSID in ('cb', '6')
    group by a.VENDORID
    )

Answer 1

对于包含最新JSON value of the Name field { } nil {name: ""} pointer to "" 的单行：

[Last Date Received]

对于使用top with ties row_number()的每个select top 1 * from ( select a.vendorid, a.DOCDATE as [Last Date Received], b.VENDNAME as [Vendor Name] from PM20000 a inner join PM00200 b on a.VENDORID = b.VENDORID where b.VNDCLSID in ('cb', '6') union all select a.VENDORID, a.DOCDATE as [Last Date Received], b.VENDNAME as [Vendor Name] from PM30200 a inner join PM00200 b on a.VENDORID = b.VENDORID where b.VNDCLSID in ('cb', '6') ) u order by [Last Date Received] desc 的最新[Last Date Received]：

VendorId

使用公共表表达式并按select top 1 with ties * from ( select a.vendorid, a.DOCDATE as [Last Date Received], b.VENDNAME as [Vendor Name] from PM20000 a inner join PM00200 b on a.VENDORID = b.VENDORID where b.VNDCLSID in ('cb', '6') union all select a.VENDORID, a.DOCDATE as [Last Date Received], b.VENDNAME as [Vendor Name] from PM30200 a inner join PM00200 b on a.VENDORID = b.VENDORID where b.VNDCLSID in ('cb', '6') ) u order by row_number() over (partition by VendorId order by [Last Date Received] desc) 排序：

[Last Date Received] desc

<小时/> 没有公用表表达式...

;with cte as (
  select top 1 with ties *
  from (
      select a.vendorid,
          a.DOCDATE as [Last Date Received],
          b.VENDNAME as [Vendor Name] 
      from PM20000 a
      inner join PM00200 b on a.VENDORID = b.VENDORID
      where b.VNDCLSID in ('cb', '6')
      union all
      select a.VENDORID,
          a.DOCDATE as [Last Date Received],
          b.VENDNAME as [Vendor Name] 
        from PM30200 a
      inner join PM00200 b on a.VENDORID = b.VENDORID
      where b.VNDCLSID in ('cb', '6')
    ) u
  order by row_number() over (partition by VendorId order by [Last Date Received] desc)
)
select 
    VendorId
  , VendorName
  , [Last Date Received]
  , Days_LastInvoiced = datediff(day,[Last Date Received],getdate())
from cte
order by [Last Date Received] desc

Answer 2

出于性能原因，我建议您在执行TOP之前执行UNION 。 。 。并使用UNION ALL：

select top 1 *
from ((select top 1 a.vendorid, max(a.DOCDATE) as [Last Date Received],
              max(b.VENDNAME) as [Vendor Name]
       from PM20000 a inner join
            PM00200 b
            on a.VENDORID = b.VENDORID
      where b.VNDCLSID in ('cb', '6')
      group by a.VENDORID
      order by [Last Date Received] desc
     )
     union all
     (select top 1 a.VENDORID, max(a.DOCDATE) as [Last Date Received],
             max(b.VENDNAME) as [Vendor Name] 
      from PM30200 a inner join
           PM00200 b
           on a.VENDORID = b.VENDORID
      where b.VNDCLSID in ('cb', '6')
      group by a.VENDORID
      order by [Last Date Received] desc
    )
   ) tt
order by [Last Date Received] desc;

正如SQLZim指出的那样，如果你重复，请使用with ties。