I was trying to do something like a. is base data, b are updates <snip> select coalesce(b.col1, a.col1), coalesce (b.col1, a.col1) as var, a.col3 from a left join b on coalsece (a.col, 'X') = coalesce (b.col1, 'X') -- could be null and a.col3 = b.col3 -- up to here thare are no problems and the results are correct and I have many rows with var = 7 where coalesce(b.col1, a.col1) = 7 -- I get no results whatever <snip> The question is: Can I use coalesce in the where clause or whatI an doing is too confusing to SQLite. I yhink that this would work on SQL Server ZA