MySQL COUNT() across multiple columns

Question

I have been banging my head over this one for quite a while now but can not seem to get it working :(

I have a table which among other standard fields, also has a few fi

Answer 1

SELECT
  COUNT(DISTINCT val_1) AS val_1_count,
  COUNT(DISTINCT val_2) AS val_2_count,
  ...
FROM ...

will give you the counts for each field.

SELECT val_1, count(*) as val_1_count
FROM ...
GROUP BY val_1

will give you the counts for a value. You can use UNION to repeat this for val_1 to val_n in a single (kludgy) query.

If you want the counts over all fields, you need

SELECT val,count(*) as valcount
FROM (
  SELECT val_1 AS val FROM ...
  UNION ALL
  SELECT val_2 AS val FROM ...
  ...
) AS baseview
GROUP BY val