SolvedPrivate

Select multiple tables in LINQ

Posted on 2014-09-04
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Last Modified: 2016-02-15
Hi Experts,

I have this SQL query statement:

SELECT d1.*
FROM FinanceDept d1
INNER JOIN
(SELECT User_ID, MAX(SalesAmt) AS 'Amount' FROM SalesDept GROUP BY User_ID) d2
ON d1.User_ID = d2.User_ID AND d1.Amount= d2.Amount

But I don't know how to write it in LINQ and Lambda expression.
Please help.

Thank you
0
Comment
Question by:alexcryout
[X]
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5 Comments
 
LVL 70

Accepted Solution

by:
Éric Moreau earned 250 total points
ID: 40305509
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LVL 63

Assisted Solution

by:Fernando Soto
Fernando Soto earned 250 total points
ID: 40305938
Hi alexcryout;

Try this query and see if it returns the required results.

var results = from d1 in FinanceDept
              join d2 in SalesDept on new { d1.User_ID, d1.Amount  } equals new { d.OrderID, d2.Amount } into userGroup
              orderby d1.User_ID
              select new 
              {
                 FinanceDept = d1,
                 User_ID_d2 = userGroup.Select( u => u.User_ID ).FirstOrDefault(),
                 Amount = userGroup.Max( a = a.SalesAmt )
              };

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0
 

Author Comment

by:alexcryout
ID: 40306230
Hi Fernando,

Sorry for my typo, I am trying to join the same table. The correct SQL statement is:

SELECT d1.*
 FROM FinanceDept d1
 INNER JOIN
 (SELECT User_ID, MAX(SalesAmt) AS 'Amount' FROM FinanceDept GROUP BY User_ID) d2
 ON d1.User_ID = d2.User_ID AND d1.Amount= d2.Amount

Thanks
0
 
LVL 63

Expert Comment

by:Fernando Soto
ID: 40306311
Hi alexcryout;

Just substitute the table name SalesDept with FinanceDept as shown in this line of the query and that should do it.

(SELECT User_ID, MAX(SalesAmt) AS 'Amount' FROM FinanceDept GROUP BY User_ID) d2
0
 

Author Closing Comment

by:alexcryout
ID: 40306382
It works fine but I download the Linqer tool and its solution is much better.

Thank you for all your helps.
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