子查詢Group By子句

在AdventureWorks2012數據庫，我必須寫一個查詢，顯示從Sales.SalesOrderHeader表並從Sales.SalesOrderDetail表子查詢Group By子句

嘗試1

SELECT * 
FROM Sales.SalesOrderHeader 
    (SELECT AVG (LineTotal) 
    FROM Sales.SalesOrderDetail 
    WHERE LineTotal <> 0) 
GROUP BY LineTotal

平均LineTotal所有列

我得到以下錯誤：

Msg 156, Level 15, State 1, Line 3 
Incorrect syntax near the keyword 'SELECT'. 
Msg 102, Level 15, State 1, Line 5 
Incorrect syntax near ')'.

嘗試2

SELECT * 
FROM Sales.SalesOrderHeader h 
    JOIN (
    SELECT AVG(LineTotal) 
    FROM Sales.SalesOrderDetail d 
    GROUP BY LineTotal) AS AvgLineTotal 
ON d.SalesOrderID = h.SalesOrderID

我得到以下錯誤：

Msg 8155, Level 16, State 2, Line 7 
No column name was specified for column 1 of 'AvgLineTotal'. 
Msg 4104, Level 16, State 1, Line 7 
The multi-part identifier "d.SalesOrderID" could not be bound.

子查詢是對我來說非常混亂。我究竟做錯了什麼？謝謝。

來源

2014-01-13 user3047713

來吧，你要問你的任務的每個人？ http://stackoverflow.com/questions/21096582/sql-subqueries-errors，http://stackoverflow.com/questions/20501110/sql-total-quanity-purchased-by-year，http://stackoverflow.com/問題/ 20499184/sql-total-quantity-and-sum – Lamak

好吧，你正在混合你的別名和一些其他的東西。

第二個版本看起來應該

SELECT h.*, d.avgLineTotal 
FROM Sales.SalesOrderHeader h 
    JOIN (
    SELECT SalesOrderID, --you need to get this to make a join on it 
    AVG(LineTotal)as avgLineTotal --as stated by error, you have to alias this (error 1) 
    FROM Sales.SalesOrderDetail 
    GROUP BY SalesOrderID) d --this will be used as subquery alias (error 2) 
ON d.SalesOrderID = h.SalesOrderID

另一個解決辦法是

select h.field1, h.field2, -- etc. all h fields 
coalesce(AVG(sod.LineTotal), 0) 
from Sales.SalesOrderHeader h 
LEFT JOIN Sales.SalesOrderDetail d on d.SalesOrderID = h.SalesOrderID 
GROUP BY h.field1, h.field2 --etc. all h fields

來源

2014-01-13 20:05:46

感謝您的幫助。 – user3047713

子查詢Group By子句

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