如何解决将 SQL 输出格式化为 JSON 的最佳方法?
一直在尝试执行 sql 查询并输出完美的 JSON,但我遇到了问题。查询仅涉及表,当我使用“For JSON Auto”时,它会生成一个平面对象数组:enter image description here
但是存在层级关系:
Q2CNum--- 订单项---- 标识符
我尝试使用“For JSON Path”,但它只构建每个 json 对象(例如,它不会聚合其父 LineItem 下的所有标识符)。
我设法通过将表连接到自身来使它看起来像这样(相同的查询只是额外的连接,“For JSON Path Auto”似乎喜欢这个),它看起来更像这样:{{3} }
哪个好。问题是查询时间几乎是原来的 20 倍(2 秒 vs 20)。
也许我的自联接写得不好,或者联接以获得这些结果效率低下。
无论如何,如果有人知道如何做到这一点,请告诉我(不能分享太多,我相信您已经注意到图像上的颜色遮挡)。
更新:
这是查询 enter image description here 的图片。问题是我得到了一个扁平的 JSON(只是一个对象数组)。
Select OWS.Q2CNum,OWS.LineItem,OWS.Identifier,OWS.ProductType,OWS.Workstation,OWS.Calculation,OWS.UnitOfMeasure,OWS.CurrentStatus,LS.Location,LS.ProgramStamp_LocalTime
FROM table1 AS OWS
INNER JOIN table2 AS LS
ON OWS.Q2CNum = LS.[Order]
AND OWS.LineItem = LS.LineItem
AND OWS.Identifier = LS.Identifier
WHERE LS.ProgramStamp_LocalTime =
(Select TOP 1 LS2.ProgramStamp_LocalTime
from dbo.view_Location_Stamps_Local AS LS2
Where LS2.[Order] = OWS.Q2CNum
AND LS2.LineItem= OWS.LineItem
AND LS2.Identifier = OWS.Identifier
Order by LS2.ProgramStamp_LocalTime Desc)
AND LS.[Order] = @testvar
AND LS.LineItem = COALESCE('001',OWS.LineItem)
AND LS.Identifier like '%'
---Group by Q2CNum
ORDER BY Q2CNum,LineItem,Identifier DESC
FOR JSON Auto
但我需要它是分层的:
{
Q2CNum: value,LineItems: [{
LineItem: value,Identifiers: [{
identifier: value,etc...
}],}],}
更新 2:
如果我运行这个查询,我会得到更多我想要的:
Select Q2C.Q2CNum,Li.LineItem,LS.ProgramStamp_LocalTime
FROM table1 AS OWS
INNER JOIN table2 AS Q2C
ON Q2C.Q2CNum = OWS.Q2CNum and Q2C.LineItem = OWS.LineItem and Q2C.Identifier = OWS.Identifier and Q2C.Workstation = OWS.Workstation
INNER JOIN table3 AS Li
ON Li.Q2CNum = OWS.Q2CNum and Li.LineItem = OWS.LineItem and Li.Identifier = OWS.Identifier and Li.Workstation = OWS.Workstation
INNER JOIN table4 AS LS
ON OWS.Q2CNum = LS.[Order]
AND OWS.LineItem = LS.LineItem
AND OWS.Identifier = LS.Identifier
WHERE LS.ProgramStamp_LocalTime =
(Select TOP 1 LS2.ProgramStamp_LocalTime
from table5 AS LS2
Where LS2.[Order] = OWS.Q2CNum
AND LS2.LineItem= OWS.LineItem
AND LS2.Identifier = OWS.Identifier
Order by LS2.ProgramStamp_LocalTime Desc)
AND LS.[Order] = @testvar
AND LS.LineItem = COALESCE('001',Identifier DESC
FOR JSON Auto
但查询时间较长。
最终更新:
好的,所以 Mike Petri 的解决方案有效。我不得不修补它并试图将我的头围绕它(仍在这样做 - 在此之前我对我的 sql 技能更有信心)。无论如何,这里是我使用的最终代码(上半部分并不重要,我已经编写了该查询,唯一重要的是使用临时表。我会使用视图,但我有资源限制,所以这是更好的自动取款机)。真正的魔法开始于查询的下半部分:
IF OBJECT_ID('tempdb..#Temp') IS NOT NULL
BEGIN
DROP TABLE #Temp;
END;
SELECT OWS.Q2CNum,LS.ProgramStamp_LocalTime
INTO #Temp
FROM table1 AS OWS
INNER JOIN table2 AS LS ON OWS.Q2CNum = LS.[Order]
AND OWS.LineItem = LS.LineItem
AND OWS.Identifier = LS.Identifier
WHERE LS.ProgramStamp_LocalTime = (
SELECT TOP 1
LS2.ProgramStamp_LocalTime
FROM talbe3 AS LS2
WHERE LS2.[Order] = OWS.Q2CNum
AND LS2.LineItem = OWS.LineItem
AND LS2.Identifier = OWS.Identifier
ORDER BY
LS2.ProgramStamp_LocalTime DESC
)
AND LS.[Order] = @testvar
AND LS.LineItem = COALESCE('001',OWS.LineItem)
AND LS.Identifier LIKE '%';
----REAL MAGIC HAPPENS HERE
SELECT t.Q2CNum,(
SELECT disTINCT(t2.LineItem),(
SELECT disTINCT(t3.Identifier),t3.Location,t3.ProgramStamp_LocalTime,(
SELECT t4.Workstation,t4.ProductType,t4.Calculation,t4.UnitOfMeasure,t4.CurrentStatus
FROM #Temp AS t4
WHERE t3.Q2CNum = t4.Q2CNum and t3.LineItem = t4.LineItem and t3.Identifier = t4.Identifier
FOR JSON PATH
) AS Workstations
FROM #Temp AS t3
WHERE t3.Q2CNum = t2.Q2CNum and t2.LineItem = t3.LineItem
FOR JSON PATH
) AS Identifiers
FROM #Temp AS t2
WHERE t.Q2CNum = t2.Q2CNum
FOR JSON PATH
) AS LineItems
FROM (
SELECT disTINCT
Q2CNum
FROM #Temp
) AS t
FOR JSON AUTO;
DROP TABLE #Temp;
欢迎所有批评(我想知道的一件事是过滤(使用 Where 子句)同心 sql 选择的正确方法,即表 t4 应该只过滤到表 t3(它是直接的 Hierarchal 父级?)还是我还应该添加约束到 t4 和 t2?还是 t4 和 t?
解决方法
我使用“FOR JSON PATH”作为列表 和“对于 JSON 路径,WITHOUT_ARRAY_WRAPPER”用于项目
,看看这是否能让你更接近。 由于您涉及连接,因此引用内部/外部查询会变得很危险。您可以将基本查询设为 VIEW,然后替换 #Temp 引用,或者使用下面的代码将其存储在临时表中,然后通过内部表引用外部表以获得您所追求的分组。>
IF OBJECT_ID('tempdb..#Temp') IS NOT NULL
BEGIN
DROP TABLE #Temp;
END;
SELECT OWS.Q2CNum,OWS.LineItem,OWS.Identifier,OWS.ProductType,OWS.Workstation,OWS.Calculation,OWS.UnitOfMeasure,OWS.CurrentStatus,LS.Location,LS.ProgramStamp_LocalTime
INTO #Temp
FROM table1 AS OWS
INNER JOIN table2 AS LS ON OWS.Q2CNum = LS.[Order]
AND OWS.LineItem = LS.LineItem
AND OWS.Identifier = LS.Identifier
WHERE LS.ProgramStamp_LocalTime = (
SELECT TOP 1
LS2.ProgramStamp_LocalTime
FROM dbo.view_Location_Stamps_Local AS LS2
WHERE LS2.[Order] = OWS.Q2CNum
AND LS2.LineItem = OWS.LineItem
AND LS2.Identifier = OWS.Identifier
ORDER BY
LS2.ProgramStamp_LocalTime DESC
)
AND LS.[Order] = @testVar
AND LS.LineItem = COALESCE('001',OWS.LineItem)
AND LS.Identifier LIKE '%';
SELECT t.Q2CNum,(
SELECT t2.LineItem,(
SELECT t2.Identifier AS value,t2.ProductType,t2.Workstation,t2.Calculation,t2.UnitOfMeasure,t2.CurrentStatus,t2.Location,t2.ProgramStamp_LocalTime
FOR JSON PATH
) AS Identifiers
FROM #Temp AS t2
WHERE t.Q2CNum = t2.Q2CNum
FOR JSON PATH,WITHOUT_ARRAY_WRAPPER
) AS LineItems
FROM (
SELECT DISTINCT
Q2CNum
FROM #Temp
) AS t
FOR JSON AUTO;
DROP TABLE #Temp;
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