[TYPO3-dev] TCA - type select, select from joined tables?

[Brian Bendtsen]

Hi
I have never figured this out, how do I join tables in the TCA. I would 
like to have a select box where it is possible to select from values in 
a recordset thats created from joining a few tables.

My sql looks something like this:

SELECT table1.name FROM table1, table2, table3, table4 WHERE 
table1.primKey = table2.foreignKey AND table2.primKey = 
table3.ForeignKey AND table3.primKey = table4.ForeignKey AND 
table4.primKey = 134 AND table3.field2 = 1 AND table2.field3 = 1;

Any help is appreciated

In the api manual, in the advanced lookup section a "itemsProcFunc" is 
mentioned, but its not explained much.

Is there some more docs about this somewhere? Or some examples?

/Brian