Getting a SQL Query to work in Access - sql

Question

I have the following Query written in MS SQL Server:
select
(select (CAST( count(*) as decimal (38,4))) from Inventor) /
(select (CAST( count(*) as decimal(38,4))) from General);
which works perfectly, but when I try to use it in Access it doesn't work at all.
Help please!
Ok so it doesnt have to be cast as decimal, a float would work as well.
My Inventor table has the PK from the General table as a FK in it. The issue is that if something has multiple inventors listed on it. So i Tried the following:
SELECT TotalInventors/TotalPatents
(SELECT COUNT (DISTINCT PatentNo) FROM Inventor AS TotalPatents
(SELECT COUNT (*) FROM Inventor AS TotalInventors))
FROM Inventor;
Still with a syntax error

Answer 1

The syntax for Select in Access does NOT allow you to write a select without a "from".
Access Grammar:
SELECT [predicate] { * | table.* | [table.]field1 [AS alias1] [, [table.]field2 [AS alias2] [, ...]]}
FROM tableexpression [, ...] [IN externaldatabase] --FROM is NOT optional
[WHERE... ]
[GROUP BY... ]
[HAVING... ]
[ORDER BY... ]
[WITH OWNERACCESS OPTION]
SQL Server Grammar:
[ WITH <common_table_expression>]
SELECT select_list [ INTO new_table ]
[ FROM table_source ] [ WHERE search_condition ] --FROM is optional
[ GROUP BY group_by_expression ]
[ HAVING search_condition ]
[ ORDER BY order_expression [ ASC | DESC ] ]
As you can see here, the [ ] mean that something is optional. And the [ ] are wrapping the "From" the SQL Server Grammar, but not in the Access Grammar.
So, basically, your query is invalid in Access because it needs a "FROM"
Now this is a little bit inconsistent, while this :
select ( 1 ) / ( 1 )
Or this
select ( 1 )
will get me a valid answer, this will give me a syntax error in Access (but it does work in SQL Server):
select ( select 1 ) / ( select 1 )
You need a "dual" table, so that you can write:
select ( select 1 from Dual) / ( select 1 from Dual) from Dual.
Here is how you can create one

Answer 2

In the current version of your question, Access complains with this part of your query because Access SQL doesn't support COUNT (DISTINCT anything).
SELECT COUNT (DISTINCT PatentNo) FROM Inventor
You could rewrite that piece as:
SELECT Count(*) FROM
(SELECT DISTINCT PatentNo
FROM Inventor);
However adapting the full query to use that will be more challenging. Consider whether a single Access query to give you TotalInventors/TotalPatents is really the best way to go. I suspect you could make the SQL coding task easier for yourself by splitting that into 2 queries (one to give you TotalInventors and another to give you TotalPatents). Then do the division in your client code which calls the queries.

Answer 3

I think this will work:
SELECT
CDbl( ci ) / CDbl( cg ) AS result
FROM
(SELECT COUNT(*) AS ci FROM Inventor) AS i
,
(SELECT COUNT(*) AS cg FROM General) AS g ;
The comma , would be written as CROSS JOIN in other DBMS.