带有Access数据库的VB.Net中的SQL子查询

Question

I have developed an SQL query that uses sub-query based on a result set (ie a query queries the results of a sub-query). The query executes as expected in MS Access but will not execute in vb.net (including query builder). The error I receive in query builder is:

Error in WHERE clause near 'ORDER'. Unable to parse query text.

I understand that a typical sub-query selects based on the WHERE clause whereas my SQL is querying based on the FROM clause. Because Access doesn't support the LIMIT command, I can't figure out how structure this SQL so it will run in VB.NET. If the LIMIT command was supported I think I could structure the sub-query properly.

Here is my SQL:

SELECT AVG(Differential) * .96
FROM            
   (SELECT TOP 5 Differential
    FROM            
      (SELECT TOP 10 GameDate, Differential
       FROM ScoringHistory
       WHERE PlayerID = ?
       ORDER BY GameDate DESC)
    ORDER BY Differential ASC, GameDate DESC)

If I change PlayerID = ? to PlayerID = 1 (which is a valid value), query builder gives me the same error as above but I can execute the query in query builder.

I've also tried importing ( ? ) the query from Access into VB.NET and I get the same error.

Any suggestions on how to structure my query so it will execute properly?

Adding more information :

I am implementing via a table adapter. See image. Selecting the query and clicking configure displays the following

Then if I click on the Query Builder button I get this error: Error Message

My code to implement the query looks like this:

        Dim factor As Single
        factor = ScoringHistoryTableAdapter.CalculateFactor(1)

Answer 1

i think you are missing alis name or your subquery

SELECT AVG(Differential) * .96
FROM            
   (SELECT TOP 5 Differential
    FROM            
      (SELECT TOP 10 GameDate, Differential
       FROM ScoringHistory
       WHERE PlayerID = 1
       ORDER BY GameDate DESC) a
    ORDER BY Differential ASC, GameDate DESC) b

Answer 2

It looks like your OrderBy clauses are reversed.

You're ordering by GameDate in the middle From clause, but GameDate isn't included in that Select, only Differential.

Try:

    SELECT AVG(Differential) * .96
    FROM (
          SELECT TOP 5 Differential
          FROM (
                SELECT TOP 10 GameDate, Differential
                FROM ScoringHistory
                WHERE PlayerID = ?
                ORDER BY Differential ASC,GameDate DESC
               )
         ORDER BY Differential DESC
         )

Answer 3

As the original poster I thought I would close the loop for everyone on this.

A little more research indicates that this is a known problem(?) with sub queries and the table adapter wizard. Now knowing this, i learned how to execute SQL the old fashioned way and used ExecuteScalar as Charles had indicated and the SQL works fine.