Sorry. My knowledge of the data governance space is almost nil, and my knowledge of data catalog products isn't much better. I guess my larger point was that

Sorry. My knowledge of the data governance space is almost nil, and my knowledge of data catalog products isn't much better. I guess my larger point was that explaining SQL statements replicates much of the work that query optimizers do. And even they don't always get it right. It's a hard problem. If you want a hard problem with potential for a marketable product, look into data cleaning.