I've been thinking for a while about building a tool to generate ETL/ELT jobs for data warehousing. Yes, there are lots of such tools already, but I've become f

I've been thinking for a while about building a tool to generate ETL/ELT jobs for data warehousing. Yes, there are lots of such tools already, but I've become frustrated in one way or another with all that I've used so far (mainly with their bloated size and clunky "repositories" and inscrutable runtime engines). This "while" that I've been thinking is stretching out -- the other day I stumbled across my earliest vague musings on the subjects, and noted that they are a couple of years old already, so I'm beginning to think it's time to stop thinking and start building... For various reasons -- mainly familiarity, FOSS ecosystem, and cross-platform compatibility -- I'm going to try to implement this in Free Pascal / Lazarus. There is one kind of component I'm definitely going to need, and if there were a ready-made one I could use in stead of building one from scratch, it would save me a lot of time and effort. I've looked around online, but so far haven't found "the perfect one". So, my question is: Can anyone recommend a good FOSS graphical SQL query builder component -- i.e, one which presents tables and their columns to the end user, so they can specify joins and filters by clicking and dragging, etc -- for Lazarus (or in a pinch Delphi, to port to FP/L)?