sql - Replace no result

Question

I have a query like this:

SELECT TV.Descrizione as TipoVers, 
       sum(ImportoVersamento) as ImpTot, 
       count(*) as N,
       month(DataAllibramento) as Mese
FROM PROC_Versamento V
left outer join dbo.PROC_TipoVersamento TV
    on V.IDTipoVersamento = TV.IDTipoVersamento
inner join dbo.PROC_PraticaRiscossione PR 
    on V.IDPraticaRiscossioneAssociata = PR.IDPratica
inner join dbo.DA_Avviso A
    on PR.IDDatiAvviso = A.IDAvviso
where DataAllibramento between '2012-09-08' and '2012-09-17' and  A.IDFornitura = 4
group by V.IDTipoVersamento,month(DataAllibramento),TV.Descrizione
order by V.IDTipoVersamento,month(DataAllibramento)

This query must always return something. If no result is produced a

0 0 0 0

row must be returned. How can I do this. Use a isnull for every selected field isn't usefull.

score 2 · Accepted Answer

使用COALESCE。它返回第一个非空值。例如

SELECT COALESCE(TV.Desc, 0)...

如果 TV.DESC 为 NULL，将返回 0。

score 2 · Accepted Answer

使用具有一行的派生表，并对您的其他表/查询执行外部应用。

这是一个用表变量@T代替真实表的示例。

declare @T table
(
  ID int,
  Grp int
)

select isnull(Q.MaxID, 0) as MaxID,
       isnull(Q.C, 0) as C
from (select 1) as T(X)
  outer apply (
              -- Your query goes here
              select max(ID) as MaxID,
                     count(*) as C
              from @T
              group by Grp
              ) as Q
order by Q.C -- order by goes to the outer query

这将确保您在输出中始终至少有一行。

像这样使用您的查询。

select isnull(Q.TipoVers, '0') as TipoVers, 
       isnull(Q.ImpTot, 0) as ImpTot, 
       isnull(Q.N, 0) as N,
       isnull(Q.Mese, 0) as Mese
from (select 1) as T(X)
  outer apply (
              SELECT TV.Descrizione as TipoVers, 
                     sum(ImportoVersamento) as ImpTot, 
                     count(*) as N,
                     month(DataAllibramento) as Mese,
                     V.IDTipoVersamento
              FROM PROC_Versamento V
              left outer join dbo.PROC_TipoVersamento TV
                  on V.IDTipoVersamento = TV.IDTipoVersamento
              inner join dbo.PROC_PraticaRiscossione PR 
                  on V.IDPraticaRiscossioneAssociata = PR.IDPratica
              inner join dbo.DA_Avviso A
                  on PR.IDDatiAvviso = A.IDAvviso
              where DataAllibramento between '2012-09-08' and '2012-09-17' and  A.IDFornitura = 4
              group by V.IDTipoVersamento,month(DataAllibramento),TV.Descrizione
              ) as Q
order by Q.IDTipoVersamento, Q.Mese

score 0 · Accepted Answer

你可以试试：

with    dat as (select    TV.[Desc] as TipyDesc, sum(Import) as ToImp, count(*) as N, month(Date) as Mounth
                from        /*DATA SOURCE HERE*/ as TV
                group by    [Desc], month(Date))
    select    [TipyDesc], ToImp, N, Mounth from    dat
    union all
    select    '0', 0, 0, 0 where    (select count (*) from dat)=0

那应该做你想要的......

score -3 · Accepted Answer

If it's ok to include the "0 0 0 0" row in a result set that has data, you can use a union:

SELECT TV.Desc as TipyDesc, 
   sum(Import) as TotImp, 
   count(*) as N,
   month(Date) as Mounth
   ...
UNION
SELECT
    0,0,0,0

Depending on the database, you may need a FROM for the second SELECT. In Oracle, this would be "FROM DUAL". For MySQL, no FROM is necessary

sql - Replace no result

4 回答 4

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