如何嵌套多個SQL查詢？

有人可以告訴我如何將這些查詢嵌套到一個完整的查詢中嗎？現在，我一次只運行一個（最多10個），但我想學習如何在單個鏡頭中運行此查詢。如何嵌套多個SQL查詢？

Dim queryString1 As String = 
"SELECT EMPLOYEE_NAME, AVG(EFFICIENCY_YIELD) AS YIELD 
FROM dbo.APE_BUSDRIVER_MAIN 
WHERE APE_AREA_OBJID = " & lblAreaOBJID.Text & " 
AND ACTIVE = 1 
GROUP BY EMPLOYEE_NAME ORDER BY YIELD " & lblSortOrder.Text & "" 


Dim queryString2 As String = 
"SELECT EMPLOYEE_NAME, AVG(EFFICIENCY_YIELD) AS YIELD 
FROM dbo.APE_BUSDRIVER_MAIN 
WHERE APE_AREA_OBJID = " & lblAreaOBJID.Text & " 
AND ACTIVE = 1 
AND EMPLOYEE_NAME <> '" & LblStckRnk1.Text & "' 
GROUP BY EMPLOYEE_NAME 
ORDER BY YIELD " & lblSortOrder.Text & "" 


Dim queryString3 As String = 
"SELECT EMPLOYEE_NAME, AVG(EFFICIENCY_YIELD) AS YIELD 
FROM dbo.APE_BUSDRIVER_MAIN 
WHERE APE_AREA_OBJID = " & lblAreaOBJID.Text & " 
AND ACTIVE = 1 
AND EMPLOYEE_NAME <> '" & LblStckRnk1.Text & "' 
AND EMPLOYEE_NAME <> '" & LblStckRnk2.Text & "' 
GROUP BY EMPLOYEE_NAME 
ORDER BY YIELD " & lblSortOrder.Text & ""

來源

2013-12-20 Joseph.Scott.Garza

我會用幾個UNION語句：

Dim queryString1 As String = "SELECT EMPLOYEE_NAME, AVG(EFFICIENCY_YIELD) AS YIELD 
    FROM dbo.APE_BUSDRIVER_MAIN WHERE APE_AREA_OBJID = " & lblAreaOBJID.Text & " AND ACTIVE = 1 
    GROUP BY EMPLOYEE_NAME ORDER BY YIELD " & lblSortOrder.Text & vbCrLf & _ 

" UNION " & vbCrLf & _ 

"SELECT EMPLOYEE_NAME, AVG(EFFICIENCY_YIELD) AS YIELD 
    FROM dbo.APE_BUSDRIVER_MAIN 
    WHERE APE_AREA_OBJID = " & lblAreaOBJID.Text & " AND ACTIVE = 1 
    AND EMPLOYEE_NAME <> '" & LblStckRnk1.Text & "' 
    GROUP BY EMPLOYEE_NAME ORDER BY YIELD " & lblSortOrder.Text & vbCrLf & _ 

" UNION " & vbCrLf & _ 

"SELECT EMPLOYEE_NAME, AVG(EFFICIENCY_YIELD) AS YIELD 
    FROM dbo.APE_BUSDRIVER_MAIN 
    WHERE APE_AREA_OBJID = " & lblAreaOBJID.Text & " AND ACTIVE = 1 
    AND EMPLOYEE_NAME <> '" & LblStckRnk1.Text & "' AND EMPLOYEE_NAME <> '" & LblStckRnk2.Text & "' 
    GROUP BY EMPLOYEE_NAME ORDER BY YIELD " & lblSortOrder.Text

（當然，你將要刪除多餘的換行符，我增加了可讀性）

來源

2013-12-20 16:53:17 tgolisch

OK涼爽。我會嘗試的。謝謝！ –

問題：如何生成第二個聯合查詢的itemID？我想如果我使用CType（Reader.Item（2），字符串）我將能夠獲得第二個員工，但即時通訊「索引超出數組的界限。」錯誤 –

ItemID不是結果集的一部分。您需要將其添加到三個查詢中的每一個。請記住，Reader.Item（2）引用SELECT語句中的第三項（並且只指定了兩個項目）。 – tgolisch

讓我們來看看這是什麼查詢返回：

（所有三個通過使用相同的基團和以相同的順序）

1-返回所有的「活性」員工「areaFooBar」

2-返回在「areaFooBar」所有的「活性」僱員MINUS一個僱員

3-返回所有的「活性」員工「areaFooBar 「減去兩位員工

您可以在代碼中進行這種過濾。您不必運行查詢2或查詢3. 重新查詢查詢1的結果集並過濾不想包含的員工。

您可以從數據庫中每一次讀它，那麼你可以使用一個的queryString如果你一個參數添加到您的查詢即：逗號分隔list.Text

Dim queryString1 As String = 
" 
SELECT EMPLOYEE_NAME, AVG(EFFICIENCY_YIELD) AS YIELD 
FROM dbo.APE_BUSDRIVER_MAIN 
WHERE APE_AREA_OBJID = " & lblAreaOBJID.Text & " 
AND ACTIVE = 1 
EMPLOYEE_NAME NOT IN (" & comma-separated-list.Text & ") 
GROUP BY EMPLOYEE_NAME ORDER BY YIELD " & lblSortOrder.Text & ""

來源

2013-12-20 17:20:38

能否詳細說明逗號分隔列表。文本部分？所以，這是我需要在查詢中輸入的全部內容？ –

聲明一個varchar變量作爲逗號分隔列表。您可以使用「LblStckRnkX.Text」值填充此變量（逗號分隔列表）。即：如果不包含LblStckRnk文本，請將逗號分隔列表設置爲空字符串。如果您將通過LblStckRnk1.Text和LblStckRnk2.Text和LblStckRnk3.Text;然後將逗號分隔列表設置爲[LblStckRnk1.Text +「，」+ LblStckRnk2.Text +「，」LblStckRnk3.Text]。 –

如何嵌套多個SQL查詢？

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