Question

I’ll try to keep this as simple as possible.

There are 3 tables (A,B,C) each with a name column (and only a name column). I want to select all of the rows from the three separate tables (without duplicates), but, more importantly, to order them by number of duplicates such that if “Charles” exists in table A,B, and C, then it will show first in the results. Names that only exist in one table will come at the end of the results. Any help would be appreciated. Thanks!

Answer 1

 select name from 
(select name from A 
  UNION ALL 
 select name from B 
 UNION ALL
 select name from C) t 
group by name order by count(name) DESC