Question

情况：我正在处理的Access数据库将零件分成左右两部分。两侧可以使用相同的部件。我正在尝试创建一个查询来计算每件所需的单个零件总数。

问题：如何创建允许UNION多个字段的查询，如下所示？

示例：

Table 1:
Part # |Left Part | Left Part Qty | Right Part | Right Part Quantity
1        xyz         5               xyz          7
2        abc         8               lmn          4

Table 2:
Part # | Needed
1        10
2        25

Query:
Part | Quantity
xyz    120 ((5 + 7) * 10)
abc    200 (8 * 25) 
lmn    100 (4 * 25)

编辑：我很抱歉，但我忘了添加一部分内容。我没有意识到我需要从另一个表中乘以一个因子。

Answer 1

如果您有所有部件的表格，那么您可以这样做：

select p.part, nz(l.cnt, 0) + nz(r.cnt, 0)
from (parts as p left join
      (select leftpart, count(*) as cnt
       from table t
       group by leftpart
      ) as l
      on p.part = l.leftpart
     ) left join
     (select rightpart, count(*) as cnt
      from table
      group by rightpart
     ) as r
     on p.part = r.rightpart;

如果您没有这样的表，可以从查询创建视图：

select leftpart
from table
union
select rightpart
from table;

然后使用表格中的视图。

Answer 2

您可以这样做：

Select
    BothParts, Sum(BothQty) As TotalQuantity
From

(Select 
    [Left Part] As BothParts, [Left Part Qty] As BothQty
From
    YourTable
Union All
Select
    [Right Part] As BothParts, [Right Part Qty] As BothQty
From
    YourTable) As T

Group By BothParts;

访问UNION查询以组合多个字段

2 个答案: