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Hi all,
i have what i think is a basic need: select rows using the HAVING statement after a LEFT OUTER JOIN using the COUNT(*).

I wish to select all the lines from a table which are referred a certain number of times from another one, ex: query.where("relation_one_to_many = 0").

How can i do this?
Thanks

Hello,

Sorry I don't understand, could you please give an example ?

Off course:

Code: Select all

SELECT A.id, count(B.default_A_id) as cnt FROM A  LEFT OUTER JOIN B on default_A_id = B.id GROUP BY A.id HAVING cnt = 0


I'm using this as a free Query in conjunction with execute_query currently but i think that probably is possible to use the relationship in a standard query like:

qx::QxSqlQuery query;
query.where(" count (A.Bs )").equalsTo(0);

Supposing that Bs is a N-1 relationship defined in A using default_A_id as the FK column.

I'm using this as a free Query in conjunction with execute_query

Yes, you have to do that because qx::QxSqlQuery class doesn't support it.

Perfect, the important part for me was to accomplish this in a nice/compilant way.
If that is, i have no complains since with a little of manual writing i obtained in two line of codes an array of objects filled as needed

Thanks again for all the clarifications and support, this is making QxOrm a must-have in C++ projects IMHO.

Best regards

this is making QxOrm a must-have in C++ projects IMHO

Thx !