[Zope] Nested select or call a ZSQL method from another ZSQL?

[Christian Theune]

Hi,

the sqldelimiter is used to separate two or more querys that are executed *after* each other.

The behaviour you want is called "subselects" and is depending on you RDBMS. MySQL for example (IIRC)
doesn't have those, PostgreSQL has them.

Using PostgreSQL it might look like this:

 SELECT
    *
 FROM
    foo
 WHERE
    id = ( SELECT
                max(id)
            FROM
                bar )

* Jorge O. Martinez <jmartinez@eMediaMillWorks.com> [020610 00:10]:
> Hi:
> 
> I am not sure what is the better way to go, but I need to do a select 
> statement using some input from another zsql method. I tried using 
>  <dtml-var sql_delimiter> but didn't get it work, the query is simple:
> 
> select * from foo
> <dtml-sqlgroup where>
>  id =
> <dtml-var sql_delimiter>
> select my_id from bar where user = VAR and class = CLA
> </dtml-var sql_delimiter>
> </dtml-sqlgroup>
> 
> (I know this looks horrible, but not sure what the right syntax would be 
> for that nested where and select statements.
> --------------
> 
> The only value I pass to this method are VAR and CLA, I would then expect 
> the method to run the nested select query first, and then, once I got the 
> value for 'my_id', I would like the outer select to be executed with the 
> value I got from the nested one. I am not having luck, is the above the 
> right approach? Or would it be better to just to a separate zsql method 
> with the query inside sql_delimiter? If so, what would be the syntax?

Well. If your RDBMS doesn't support subselects, then two separated sql methods
remain your only choice.

Regards 

Christian

-- 
Christian Theune - ct@gocept.com
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