Question

我见过类似的问题，但无法找到解决这个问题的方法。承担着乱七八糟的桌子，问题应该是什么？非常坦率的。

我有下表。

LDTime                      Value
2013-07-24 00:00:00.000     14.85
2013-07-24 00:00:00.000     1.339
2013-07-24 00:15:00.000     95.9
2013-07-24 00:15:00.000     1.285
2013-07-24 00:30:00.000     160
2013-07-24 00:30:00.000     0.952

行1,3和5是一种数据。 2,4和6是另一种类型。我有以下查询可以根据过滤条件检索类型：

SELECT 
    A.LDTime, A.Value As AValue
FROM      
    Table7 G 
INNER JOIN
     Table1 A 
INNER JOIN
     Table2 B ON A.DataSetIdx = B.DataSetIdx 
INNER JOIN
     Table3 C ON B.RetrievalIdx = C.RetrievalIdx ON G.ActionIdx = C.ActionIdx 
INNER JOIN
     Table4 D ON G.SpatialRefIdx = D.SpatialRefIdx 
INNER JOIN
     Table5 E 
INNER JOIN
     Table6 F ON E.StationIdx = F.StationIDx ON D.SpatialRefIdx = E.SpatialRefIdx
WHERE 
     F.StationIDx = 1 
     AND A.ParameterIdx = 18
     AND A.LDTime BETWEEN '2013-7-24' AND '2013-7-25'
ORDER 
     BY A.LDTime


SELECT 
    A.LDTime, A.Value As BValue
FROM
    Table7 G 
INNER JOIN
    Table1 A 
INNER JOIN
    Table2 B ON A.DataSetIdx = B.DataSetIdx 
INNER JOIN
    Table3 C ON B.RetrievalIdx = C.RetrievalIdx ON G.ActionIdx = C.ActionIdx 
INNER JOIN
    Table4 D ON G.SpatialRefIdx = D.SpatialRefIdx 
INNER JOIN
    Table5 E 
INNER JOIN
    Table6 F ON E.StationIdx = F.StationIDx ON D.SpatialRefIdx = E.SpatialRefIdx
WHERE 
    F.StationIDx = 1 
    AND A.ParameterIdx = 19
    AND A.LDTime BETWEEN '2013-7-24' AND '2013-7-25'
ORDER BY 
     A.LDTime

请注意，我在两个查询之间只更改了一个过滤变量（ParameterIdx），这可以区分值列中存储的数据类型。

如何组合查询以生成一个结果集？（或者，我正在使用存储过程，因此可以在多个查询中完成）。

LDTime                      AValue   BValue
2013-07-24 00:00:00.000     14.85    1.339
2013-07-24 00:15:00.000     95.9     1.285
2013-07-24 00:30:00.000     160      0.952

Answer 1

这应该这样做：

SELECT a.LDTime
     , Avalue = MAX(CASE WHEN A.ParameterIdx = 18 THEN A.Value END)
     , BValue = MAX(CASE WHEN A.ParameterIdx = 19 THEN A.Value END)
FROM         Table7 G INNER JOIN
Table1 A INNER JOIN
Table2 B ON A.DataSetIdx = B.DataSetIdx INNER JOIN
Table3 C ON B.RetrievalIdx = C.RetrievalIdx ON G.ActionIdx = C.ActionIdx INNER JOIN
Table4 D ON G.SpatialRefIdx = D.SpatialRefIdx INNER JOIN
Table5 E INNER JOIN
Table6 F ON E.StationIdx = F.StationIDx ON D.SpatialRefIdx = E.SpatialRefIdx
WHERE F.StationIDx = 1 AND A.ParameterIdx in (18, 19)
AND A.LDTime BETWEEN '2013-7-24' AND '2013-7-25'
GROUP BY A.LDTime
ORDER BY A.LDTime

Answer 2

唯一的区别似乎是where条款。因此，以下内容应正确标记行：

SELECT A.LDTime,A.Value,
       (case when F.StationIDx = 1 AND A.ParameterIdx = 18 then 'A'
             when A.ParameterIdx = 19 then 'B'
        end) as AorB
FROM         Table7 G INNER JOIN
Table1 A INNER JOIN
Table2 B ON A.DataSetIdx = B.DataSetIdx INNER JOIN
Table3 C ON B.RetrievalIdx = C.RetrievalIdx ON G.ActionIdx = C.ActionIdx INNER JOIN
Table4 D ON G.SpatialRefIdx = D.SpatialRefIdx INNER JOIN
Table5 E INNER JOIN
Table6 F ON E.StationIdx = F.StationIDx ON D.SpatialRefIdx = E.SpatialRefIdx
WHERE F.StationIDx = 1 AND A.ParameterIdx in (18, 19)
AND A.LDTime BETWEEN '2013-7-24' AND '2013-7-25'
ORDER BY A.LDTime

要执行您想要的操作，您需要查询group by。这为您提供了所需的结果：

SELECT A.LDTime,
       max(case when A.ParameterIdx = 18 then Value end) as AValue,
       max(case when A.ParameterIdx = 19 then Value end) as BValue
FROM         Table7 G INNER JOIN
Table1 A INNER JOIN
Table2 B ON A.DataSetIdx = B.DataSetIdx INNER JOIN
Table3 C ON B.RetrievalIdx = C.RetrievalIdx ON G.ActionIdx = C.ActionIdx INNER JOIN
Table4 D ON G.SpatialRefIdx = D.SpatialRefIdx INNER JOIN
Table5 E INNER JOIN
Table6 F ON E.StationIdx = F.StationIDx ON D.SpatialRefIdx = E.SpatialRefIdx
WHERE F.StationIDx = 1 AND A.ParameterIdx in (18, 19)
AND A.LDTime BETWEEN '2013-7-24' AND '2013-7-25'
group BY A.LDTime
order by 1

SQL Server将同一个表上的多个查询组合到单个结果集中

2 个答案: