I don’t think the Sync Now button impacts SQL queries. That’s for tables. I just added a column to a select statement in a custom question, not a column to a table. As my follow-up comment stated, I was able to get the column to show up, but only after renaming one of the existing columns (I give specific names to the columns in the query).
select c1 “Col 1”, c2 “Col 2” from tbl;
select c1 “Col-1”, c2 “Col 2”, c3 “Col 3” from tbl;
I just added the dash to the first column name, which was the only thing that made the new column show up. Seems like a bug to me…