Re: Translate SQL Join to DDS LF

[Vern Hamberg <vhamberg@xxxxxxxxxxxxxxx>]

Y'all

I'm certain that we can't join PF & LF - from the manual - Join logical 
files combine different fields from more than one physical file into a 
single record.

Maybe Patrik can give a more-detailed example - I can think how we use a 
file here that has employee numbers for both an employee and its 
manager, with detail information for each according to their own 
employee number. In RPG, I can see using 2 CHAINs to the same LF, in 
order to get the names of both employee and manager on the same line of 
a report.

So what is the actual need here?

Cheers
Vern

On 7/15/2024 6:36 AM, paultherrien@xxxxxxxxxxxxxxxxxx wrote:
> I think...you can use logical file names.  Haven't tried it though.
> Can you create a LF over the PF and then join the PF & LF?
>
> -----Original Message-----
> From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Patrik Schindler
> Sent: Monday, July 15, 2024 5:11 AM
> To: Midrange Systems Technical Discussion <midrange-l@lists.midrangecom>
> Subject: Translate SQL Join to DDS LF
>
> Hello,
>
> I'm searching for the DDS equivalent of the following SQL JOIN statement:
>
> SELECT … FROM table1name
> LEFT JOIN table2name join_name ON ( … )
>
> The join_name is required when one needs to join the same table2name multiple times but interrelate the same field in table2name to different fields within table1name.
>
> These are referred in the field list as SELECT join_name.field_name FROM …
>
> The DDS compiler naturally complains about the same PFs being referred multiple times if just adding them multiple times but with different join fields. According to the DDS Reference, it's not allowed to name join specifications in pos. 19.
>
> Hints welcome.
>
> :wq! PoC
>
>
>
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