如何使用Union all获得两列结果

Question

我需要在结果上获取Get（Debe和Haber）列，我正在使用Union All，但我总是只获得这两列中的一列。

这是我的查询：

(SELECT tblfacturas.id                 AS ID, 
        tblclientes.razonsocial        AS Cliente, 
        tblfacturas.fecha              AS Fecha, 
        tblfacturas.tipocomprobante    AS Tipo, 
        tblfacturas.nrofacturacompleto AS Numero, 
        tblfacturas.total              AS Debe 
 FROM   tblfacturas 
        left join tblclientes 
               ON tblclientes.id = tblfacturas.id_cliente 
 WHERE  tblclientes.razonsocial = 'S.A.') 
UNION ALL 
(SELECT tblrecibos.id                AS ID, 
        tblclientes.razonsocial      AS Cliente, 
        tblrecibos.fecha             AS Fecha, 
        'R'                          AS Tipo, 
        tblrecibos.nrorecibocompleto AS Numero, 
        tblrecibos.total             AS Haber 
 FROM   tblrecibos 
        left join tblclientes 
               ON tblclientes.id = tblrecibos.id_cliente 
 WHERE  tblclientes.razonsocial = 'S.A.') 
ORDER  BY fecha 

Answer 1

你需要null来添加一个Debe和Haber列不存在，否则你在同一列中获得两个结果（Debe）

  SELECT TblFacturas.id as ID
  , TblClientes.razonsocial as Cliente
  ,TblFacturas.fecha as Fecha
  ,TblFacturas.tipocomprobante as Tipo
  ,TblFacturas.nrofacturacompleto as Numero
  , TblFacturas.total as Debe 
  , null as Haber 
  FROM TblFacturas 
  left join TblClientes on TblClientes.id = TblFacturas.id_cliente 
  where TblClientes.razonsocial = 'S.A.' 
UNION ALL

  SELECT TblRecibos.id 
  , TblClientes.razonsocial 
  ,TblRecibos.fecha 
  , 'R' 
  ,TblRecibos.nrorecibocompleto 
  , null 
  , TblRecibos.total 
  FROM TblRecibos 
  left join TblClientes on TblClientes.id = TblRecibos.id_cliente 
  where TblClientes.razonsocial = 'S.A.'
  order by fecha

另一个建议..你有一个列参与左连接在where子句这个工作作为一个内部连接排除行如果左连接值不存在，你应该 或移动on子句中的where条件（如果还需要非macthing行）

  SELECT TblRecibos.id 
  , TblClientes.razonsocial 
  ,TblRecibos.fecha 
  , 'R' 
  ,TblRecibos.nrorecibocompleto 
  , null 
  , TblRecibos.total 
  FROM TblRecibos 
  left join TblClientes on TblClientes.id = TblRecibos.id_cliente 
    AND  TblClientes.razonsocial = 'S.A.' 

或者如果只需要匹配行，则使用内连接

  SELECT TblRecibos.id 
  , TblClientes.razonsocial 
  ,TblRecibos.fecha 
  , 'R' 
  ,TblRecibos.nrorecibocompleto 
  , null 
  , TblRecibos.total 
  FROM TblRecibos 
  INNER join TblClientes on TblClientes.id = TblRecibos.id_cliente 
    AND  TblClientes.razonsocial = 'S.A.'