Question

I have a table with a list of names spread across five different columns. I’m trying to get the 6 most frequent distinct names. Each name will only appear in each record once. The five columns are name_1, name_2…name_5. And just for names sake call the table ‘mytable’.

Any help would be much appreciated.

Answer 1

Here’s one approach:

SELECT name, COUNT(1)
  FROM (           SELECT name_1 AS name FROM mytable
         UNION ALL SELECT name_2 AS name FROM mytable
         UNION ALL SELECT name_3 AS name FROM mytable
         UNION ALL SELECT name_4 AS name FROM mytable
         UNION ALL SELECT name_5 AS name FROM mytable
       ) AS myunion
 GROUP BY name
 ORDER BY COUNT(1) DESC LIMIT 6
;

How many rows are there in the table?