Concatenating fields - sql

Question

This is an MS Access (2010) script.
I am trying to concatenate 2 fields of a single table for 2 tables. Then I want to delete the associated record in one of the table if the concatenated field is equal in both tables (means this is a duplicate).
I know how to do that in VBA by looping through the records but I want to do that in SQL since the tables may quickly hold more than 50000 records which means the loop would go 2,500,000,000 times.
I though I could create a 2 SELECT statement in order to create the concatenated fields for both tables. The SELECT Statements will also display the ID of the underlying tables. Then I would delete the record in the appropriate table using the ID.
These are my Select statements:
SELECT [Tick] & [Div_ex_date] AS Expr2, tblBbgDivData.ID
FROM tblBbgDivData
GROUP BY [Tick] & [Div_ex_date], tblBbgDivData.ID;
And
SELECT [Security_Name] & [Div_ex_date] AS Expr1, tblArchiveBbgDivData.ID
FROM tblArchiveBbgDivData
GROUP BY [Security_Name] & [Div_ex_date], tblArchiveBbgDivData.ID;
This is my DELETE Statement:
DELETE tblArchiveBbgDivData.*
FROM (tblArchiveBbgDivData
INNER JOIN qselUniqueID_Archive ON tblArchiveBbgDivData.ID = qselUniqueID_Archive.ID)
INNER JOIN qselUniqueID_BbgDiv ON qselUniqueID_Archive.Expr1 = qselUniqueID_BbgDiv.Expr2
WHERE (((tblArchiveBbgDivData.ID)=[qselUniqueID_Archive].[ID])
AND ((qselUniqueID_Archive.Expr1)=[qselUniqueID_BbgDiv].[Expr2]));
When I hit Datasheet view, the relevant records are displayed but when I hit Run I get "Could not delete from specified tables". Any idea how I can change that?

Answer 1

Access does not work well with JOINs in a DELETE statement. You may be better off with an IN:
DELETE tblArchiveBbgDivData.*
FROM (tblArchiveBbgDivData
WHERE tblArchiveBbgDivData.ID IN
(SELECT qselUniqueID_Archive.ID
FROM qselUniqueID_Archive )
INNER JOIN qselUniqueID_BbgDiv
ON qselUniqueID_Archive.Expr1 = qselUniqueID_BbgDiv.Expr2
);
Note that your WHERE is redundant because you use the same expression in your JOIN syntax.