Question

I have this queries, but I need to make a Union for all. But each query has a different quantity of columns in the select-list, which gives me the error:

All queries combined using a UNION, INTERSECT or EXCEPT operator must have the same number of expressions in their target lists.

How can I fix this to avoid the error?

     Select 'Pregunta:(8-9-10)Totales No Coinciden' as Descripcion_Error, c_Fk_IdBoleta as Boleta,
       f_TotalAreaExtensionFinca as Extension_Total, f_TotalAreaDedicadaFinca 
       as Area_Dedicada_Finca, f_TotalAreaTenenciaFinca as Tenencia_Finca
      from Fnc_TenenciaUsoTierra
      where (f_TotalAreaExtensionFinca <> f_TotalAreaDedicadaFinca OR f_TotalAreaExtensionFinca <> f_TotalAreaTenenciaFinca) 
      AND  Fnc_TenenciaUsoTierra.c_Fk_IdBoleta = @id_Boleta


UNION 

SELECT 'Pregunta (12) El área sembrada es mayor al área dedicada a cultivos' as Descripcion_Error,
   c_Fk_IdBoleta as Boleta,
   (SELECT SUM(f_AreaDedicadaCultivos)
      FROM Fnc_TenenciaUsoTierra
      WHERE c_Fk_IdBoleta = sembrado.c_Fk_IdBoleta)
   AS AreaDedicadaCultivos,
   SUM(sembrado.f_AreaSiembra) as AreaSembrada
FROM
   Clt_Sembrado as sembrado
WHERE
   sembrado.c_Fk_IdBoleta = 45550711
GROUP BY sembrado.c_Fk_IdBoleta
HAVING SUM(sembrado.f_AreaSiembra) > (SELECT SUM(f_AreaDedicadaCultivos)
      FROM Fnc_TenenciaUsoTierra
      WHERE c_Fk_IdBoleta = sembrado.c_Fk_IdBoleta)

Answer 1

You have to have the same number of columns on each side of the UNION. You can always add dummy columns to get there – and fill them with NULLs or the “not applicable” value of your choice.

SELECT 'Pregunta (12) El área sembrada es mayor al área dedicada a cultivos' as Descripcion_Error,
   c_Fk_IdBoleta as Boleta,
   (SELECT SUM(f_AreaDedicadaCultivos)
      FROM Fnc_TenenciaUsoTierra
      WHERE c_Fk_IdBoleta = sembrado.c_Fk_IdBoleta)
   AS AreaDedicadaCultivos,
   SUM(sembrado.f_AreaSiembra) as AreaSembrada, 
   NULL as Tenencia_Finca
FROM Clt_Sembrado as sembrado