Re: next baby step in SQL: start using join -- MIDRANGE-L

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This is how Query/400 does joins - with the WHERE clause. And how we all did this before AS/400 gave us the JOIN clause. The first 4 tests in the WHERE clause are your JOIN specs - go back to your Query/400 definition in the file specification and compare to those.

RTVQMQRY does not handle type 2 or 3 joins from Query/400 - makes then all type 1 - so be sure to check if you have those in the query definition.

Basically, the first 4 tests are put into the ON clause of the JOIN, the last 2 stay in the WHERE clause.

If you have type 2 or 3, you need to use a LEFT OUTER join or an EXCEPTION join.

HTH

Vern

At 01:04 PM 3/27/2003 -0800, you wrote:

I'm somewhat of an experienced simple user of SQL, i.e., never done any joins.

I am now have what appears to be a perfect opportunity to use SQL join to greatly simplify my coding. Knowing that one can use Retrieve Query Mgmt Query (RTVQMQRY) to take a *QRYDFN and generate the SQL via ALWQRYDFN(*YES), I use WRKQRY to set up the query, get it working the way I want it to, save the *QRYDFN, and use RTVQMQRY to generate the SQL.

So, I am surprised to see that the generated SQL doesn't have any Join clauses (?) but, instead, does the join via WHERE, i.e.: FROM PQPROD/PESTCCP T01, PQPROD/PTBLCCP T02, PQPROD/PJOBHDR T03 WHERE T03.CMPNUM = T02.CMPNUM AND T01.CCPTYP = T02.TBLID AND T01.CCPNUM = T02.CCPNUM AND T01.JOBNUM = T03.JOBNUM AND( T01.JOBNUM = 'TACM0170' AND T02.CSTTYP = 'C')

The join in WRKQRY

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