子查询Group By子句

在AdventureWorks2012数据库，我必须写一个查询，显示从Sales.SalesOrderHeader表并从Sales.SalesOrderDetail表子查询Group By子句

尝试1

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

平均LineTotal所有列

我得到以下错误：

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 ')'.

尝试2

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

我得到以下错误：

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.

子查询是对我来说非常混乱。我究竟做错了什么？谢谢。

来源

2014-01-13 user3047713

来吧，你要问你的任务的每个人？ http://stackoverflow.com/questions/21096582/sql-subqueries-errors，http://stackoverflow.com/questions/20501110/sql-total-quanity-purchased-by-year，http://stackoverflow.com/问题/ 20499184/sql-total-quantity-and-sum – Lamak

好吧，你正在混合你的别名和一些其他的东西。

第二个版本看起来应该

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

另一个解决办法是

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

来源

2014-01-13 20:05:46

感谢您的帮助。 – user3047713

子查询Group By子句

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