The following SQL script works fine:

SELECT [Works_number] & [BT_SCP] & [Test_code_2] AS PSCP, Count([PSCP]) AS
Expr1
FROM Main
GROUP BY [Works_number] & [BT_SCP] & [Test_code_2];

However the following SQL script doesn't work.  The difference in the two
scripts is the added last line ORDER BY:

SELECT [Works_number] & [BT_SCP] & [Test_code_2] AS PSCP, Count([PSCP]) AS
Expr1
FROM Main
GROUP BY [Works_number] & [BT_SCP] & [Test_code_2]
ORDER BY Count([PSCP]) DESC;

When I try to run the second script, Access comes back with an 'Enter
parameter value' request for PSCP.

I rarely build my queries in SQL as I don't come from an SQL background.  I
usually build them in design view.  In design view the first query is as
follows:

Field - PSCP: [Works_number] & [BT_SCP] & [Test_code_2]
Total - Group By

Field - Expr1: [PSCP]
Total - Count

and the second query is identical except for the sort, as follows:

Field - PSCP: [Works_number] & [BT_SCP] & [Test_code_2]
Total - Group By

Field - Expr1: [PSCP]
Total - Count
Sort - Descending

Hoping someone can point out my error.  I'm guessing my problem lies in
incorrectly assuming the design grid is producing the SQL code I think it
should.

Thanks,
Pat