有条件地求和值

Question

我有这个查询：

SELECT R.IDrota, (SELECT count(*) FROM VendaVoo where ocupacao = 1 and IDvoo= V.IDvoo and V.IDrota = R.IDrota) as VENDAS  FROM voo V
JOIN VendaVoo VV ON VV.IDvoo = V.IDvoo
JOIN rota R ON V.IDrota = R.IDrota
GROUP BY R.IDrota, V.IDvoo, V.IDrota
order by IDrota

这给了我这张桌子：

此表中重复了一些“ IDrota”。我的目标是求和，以至于拥有唯一的“ IDrota”值。

Answer 1

我认为您只需要条件聚合：

SELECT R.IDrota,
       SUM(CASE WHEN vv.ocupacao = 1 THEN 1 ELSE 0 END) as Vendas
FROM voo V JOIN
     VendaVoo VV
     ON VV.IDvoo = V.IDvoo JOIN
     rota R
     ON V.IDrota = R.IDrota
GROUP BY R.IDrota
ORDER BY R.IDrota;

Answer 2

您可以使用sum()和case获得所需的结果。不需要subquery。 grouping只能通过IDrota

SELECT R.IDrota, 
    sum(case when VV.ocupacao = 1 then 1 else 0 end) as VENDAS  
FROM voo V
JOIN VendaVoo VV ON VV.IDvoo = V.IDvoo
JOIN rota R ON V.IDrota = R.IDrota
GROUP BY R.IDrota
order by R.IDrota