Basically it is, that you "shortname" tablenamea -> a1 and a2
select a1.*, ( select count(a2.id) from tablea a2 where a2.id = 'XXXX') As CountA2
FROM talbea a1
WHERE a1.ID='XXXX';
so in the syntax of matthewspatrick's example:
SELECT a1.civilident, ( SELECT count(a2.tickets from ars2 a2 where a2.tickets = 'XXXX' )
FROM ars2 a1
WHERE a1.civilident = 'XXXX';
The important thing is that you create from your table ars2 two tables that represent ars2 -> a1, a2
From these two references you can now independently query and count, where you otherwise would receive an error.
Hope I could make it clearer.
