Re: old query issue

[Vernon Hamberg <vhamberg@xxxxxxxxxxxxxxx>]

Oops = meant that for type THREE join types, things get more interesting.

On 5/2/2015 11:22 AM, Vernon Hamberg wrote:
> I agree that RTVQMQRY is not the ultimate tool to learn SQL.
>
>  But things have changed as to what that command generates.
>
> There used to be a problem that ALL join types were retrieved with 
> WHERE clauses, as you say, and as type 1 JOIN types.
>
> There were PTFs to change that - there are probably supercedes for 
> these -
>
> V5R4 - SI42309
> 6.1 - SI42345
> 7.1 - SI42363
>
> At 7.1 I just created a type 2 JOIN *QRYDFN with 3 files. I then ran 
> RTVQMQRY over it.
>
> The SELECT statement used 2 LEFT OUTER JOINs - exactly what I would 
> expect.
>
> For a type 2 JOIN *QRYDFN, things are a little more interesting - they 
> also implement it with 2 LEFT OUTER JOINs, with tests in the WHERE 
> clause for IS NULL on columns in the 2nd and 3rd dial.
>
> That could have been done with EXCEPTION JOINs, I guess - but at least 
> the JOINs are written out as true SQL JOINs.
>
> HTH
> Vern