在MySQL中组合多行时发出问题

Question

1. 我想根据以下条件构建查询
2. 我只想将总和1和2类型的总和结合起来。
3. 将2行合并为1并避免该行中的空值。

查询，

select B.ID as BillId, 
       I.Id as ItemID, 
       t.Type, 
       SUM(I.TotalPrice) as TotalPrice, 
       Case when t.Type = 1 then SUM(T.Amount) end as TaxAmountType1,
       Case when t.Type = 2 then SUM(T.Amount) end as TaxAmountType2 
  from Bill B
       inner join ItemDetails I 
           on I.BillNoID = B.ID
       inner join TaxDetails T 
           on T.ItemDetailId = I.Id
group by 
       B.ID, 
       I.Id, 
       I.TotalPrice, 
       t.Type;

请参考下面的图片，

预期产出：

'1'，'1'，NULL，'40 .00'，'3.00'，'5.00'

注意： 1.我不想使用子查询。 2.预期输出“NULL”表示我不想单独显示该列。

Answer 1

听起来这样可以解决您的问题。如果没有，请提供更多信息。

SELECT B.ID as BillId, I.Id as ItemId, 
       t.type, SUM(TotalPrice), SUM(TaxAmountType1), 
       SUM(TaxAmountType2) 
FROM Bill B 
GROUP BY BillId, ItemId, t.type

Answer 2

请勿按您尝试聚合的列进行分组。从GROUP BY中删除I.TotalPrice：

select B.ID as BillId, I.Id as ItemID, t.Type, SUM(I.TotalPrice) as TotalPrice, 
    Case when t.Type = 1 then SUM(T.Amount) end as TaxAmountType1,
    Case when t.Type = 2 then SUM(T.Amount) end as TaxAmountType2 from Bill B
inner join ItemDetails I on I.BillNoID = B.ID
inner join TaxDetails T on T.ItemDetailId = I.Id
group by B.ID, I.Id, t.Type;`

Answer 3

尝试

select B.ID as BillId, I.Id as ItemID, null as Type, SUM(I.TotalPrice) as TotalPrice, 
Case when t.Type = 1 then SUM(T.Amount) end as TaxAmountType1,
Case when t.Type = 2 then SUM(T.Amount) end as TaxAmountType2
from Bill B
inner join ItemDetails I on I.BillNoID = B.ID
inner join TaxDetails T on T.ItemDetailId = I.Id
group by B.ID, I.Id, I.TotalPrice

您不希望按类型分组，这是问题（您还可以从选择中删除＆＃34;，null作为类型＆＃34;

Answer 4

如果按t.type分组，则无法将这些实例放在同一行中。 尝试：

select B.ID as BillId, I.Id as ItemID, t.Type, SUM(I.TotalPrice) as TotalPrice, 
Case when t.Type = 1 then SUM(T.Amount) end as TaxAmountType1,
Case when t.Type = 2 then SUM(T.Amount) end as TaxAmountType2 from Bill B
inner join ItemDetails I on I.BillNoID = B.ID
inner join TaxDetails T on T.ItemDetailId = I.Id
group by B.ID, I.Id, I.TotalPrice;