Thanks for your reply! SQL::Abstract::More looks powerful, but that is a slightly different approach from what I would like. It seems like it's about generating complex SQL queries from a data structure.

I'm fine with using SQL itself as a DSL to describe SQL. However, sometimes a condition more complex than just parameter = ? is not known beforehand. E.g. we don't know whether user wants dates after, before, or between certain point(s), but the rest of the query is still the same. In such cases pre-written SQL is not enough. I usually end up concatenating generated and pre-written parts of query by hand. Possibly not the most efficient way, but that's what I'm comfortable with.

So I think there may be a tool that automates it by patching a pre-written query with some condition group(s). Hard to figure out what I'm really looking for... If I knew for sure, I'd just google instead of asking...