Multi-level counter iteration

I'm stuck on creating an algorithm as follows. I know this shouldn't be too difficult, but I simply can't get my head around it, and can't find the right description of this kind of pattern.

Basically I need a multi-level counter, where when a combination exist in the database, the next value is tried by incrementing from the right.

1 1 1 - Start position. Does this exist in database? YES -> Extract this and go to next
1 1 2 - Does this exist in database? YES -> Extract this and go to next
1 1 3 - Does this exist in database? YES -> Extract this and go to next
1 1 4 - Does this exist in database? NO -> Reset level 1, move to level 2
1 2 1 - Does this exist in database? YES -> Extract this and go to next
1 2 2 - Does this exist in database? NO -> Reset level 2 and 1, move to level 3
2 1 1 - Does this exist in database? YES -> Extract this and go to next
2 1 2 - Does this exist in database? YES -> Extract this and go to next
2 1 3 - Does this exist in database? NO -> Reset level 1 and increment level 2
2 2 1 - Does this exist in database? YES -> Extract this and go to next
2 2 2 - Does this exist in database? YES -> Extract this and go to next
2 2 3 - Does this exist in database? YES -> Extract this and go to next
2 3 1 - Does this exist in database? NO -> Extract this and go to next
3 1 1 - Does this exist in database? NO -> Extract this and go to next
3 2 1 - Does this exist in database? NO -> End, as all increments tried

There could be more than three levels, though.

In practice, each value like 1, 2, etc is actually a $value1, $value2, etc. containing a runtime string being matched against an XML document. So it's not just a case of pulling out every combination already existing in the database.