gecorreleerde query correlated subquery correlated subquery Correlated Subquery on Wikipedia wikipedia correlated subquery correlated subquery Correlated subquery – Wikipedia correlated subquery Correlated subquery Wikipedia correlated subquery subquery correlated sub-query correlated subquery correlated subquery http://en.wikipedia.org/wiki/Correlated_subquery Wikipedia page https://en.wikipedia.org/wiki/Correlated_subquery gecorreleerde query