如何用计数值和伪值聚合联合表？

Question

I am counting in two tables some stuff and want one aggregated result (one row). I write this SQL for this purpose:

SELECT  sum (Amount_New) Amount_New, 
        sum(Import_Dropout) Import_Dropout, 
        sum(Import)Import, 
        sum(Processing)Processing, 
        sum(Processing_Dropout)Processing_Dropout, 
        sum(Matching)Matching, 
        sum(Matching_Dropout)Matching_Dropout, 
        sum(Export)Export,
        sum(Exported)Exported, 
        sum(Rejected)Rejected, 
        sum(AmountSubTotal)AmountSubTotal, 
        sum(AmountTotal)AmountTotal
FROM (

SELECT  COUNT(CASE WHEN ProcessStatus='_New' THEN 1 ELSE null END) AS Amount_New,
        COUNT(CASE WHEN ProcessStatus='Import_Dropout' THEN 1 ELSE null END) AS Import_Dropout,
        COUNT(CASE WHEN ProcessStatus='Import' THEN 1 ELSE null END) AS Import,
        COUNT(CASE WHEN ProcessStatus='Processing' THEN 1 ELSE null END) AS Processing,
        COUNT(*) AS AmountTotal,
        0 as Processing_Dropout, 
        0 as Matching, 
        0 as Matching_Dropout, 
        0 as Export, 
        0 as Export_Dropout, 
        0 as Exported, 
        0 as Rejected, 
        0 as AmountSubTotal, 
        0 as UnionOrder
FROM "fileimport$marketscanimportcsv" 
WHERE  ft_boekdat like '%2018%'

UNION 

SELECT  0 AS Amount_New, 
        0 AS Import_Dropout, 
        0 AS Import, 
        COUNT(CASE WHEN ProcessStatus='Processing_Dropout' THEN 1 ELSE null END) AS Processing_Dropout,
        COUNT(CASE WHEN ProcessStatus='Processing' THEN 1 ELSE null END) AS Processing,
        COUNT(CASE WHEN ProcessStatus='Matching' THEN 1 ELSE null END) AS Matching,
        COUNT(CASE WHEN ProcessStatus='Matching_Dropout' THEN 1 ELSE null END) AS Matching_Dropout,
        COUNT(CASE WHEN ProcessStatus='Export' THEN 1 ELSE null END) AS Export,
        COUNT(CASE WHEN ProcessStatus='Export_Dropout' THEN 1 ELSE null END) AS Export_Dropout,
        COUNT(CASE WHEN ProcessStatus='Exported' THEN 1 ELSE null END) AS Exported,
        COUNT(CASE WHEN ProcessStatus='Rejected' THEN 1 ELSE null END) AS Rejected,
        COUNT(CASE WHEN ProcessStatus!= '_New' and ProcessStatus!= 'Import_Dropout' and ProcessStatus!= 'Import'  THEN 1 ELSE null END) AS AmountSubTotal,
        COUNT(*) AS AmountTotal,
        1 as UnionOrder
FROM "matching$marketscanmovement" 
WHERE date_part ('year', BookingDate_BA_MS)= 2018 

)  SK GROUP by unionorder order by unionorder asc 

1) The result is 2 rows, which is not one value as total of that column. Why is this query not summarizing the unioned same column values? How should it be written?

2) When I try sum "(Amount_New1+Amount_New2) Amount_New" (and changing the subquery column names to amount_new1 / amount_new2) it is not working neither. Why?

Answer 1

If you want to return a single row, conceptually representing an aggregate over the entire union table, then remove GROUP BY :

SELECT  SUM(Amount_New) Amount_New,
        SUM(Import_Dropout) Import_Dropout,
        SUM(Import) Import,
        SUM(Processing) Processing,
        SUM(Processing_Dropout) Processing_Dropout,
        SUM(Matching) Matching,
        SUM(Matching_Dropout) Matching_Dropout,
        SUM(Export) Export,
        SUM(Exported) Exported,
        SUM(Rejected) Rejected,
        SUM(AmountSubTotal) AmountSubTotal,
        SUM(AmountTotal) AmountTotal
FROM
(
    -- ... your current query
) SK;

You also may want to remove the UnionOrder computed column, since there is no need to sort a single row result set.