swa66 - 6:08 pm on Nov 20, 2012 (gmt 0)
Regardless you could always include an additional column you add the select it came from and then sort on that, SQL is a fully featured language. Most you can imagine to do can be done in one (complex) query.
Actually the docs state the approach by adding a column to indicate what select the row comes from
To cause rows in a UNION result to consist of the sets of rows retrieved by each SELECT one after the other, select an additional column in each SELECT to use as a sort column and add an ORDER BY following the last SELECT:
(SELECT 1 AS sort_col, col1a, col1b, ... FROM t1)
(SELECT 2, col2a, col2b, ... FROM t2) ORDER BY sort_col;
Quoted from [dev.mysql.com...]