Select distinct from multiple fields using sql

Question

I have 5 columns corresponding to answers in a trivia game database - right, wrong1, wrong2, wrong3, wrong4

I want to return all possible answers without duplicates.

Answer 1

Well you can use a UNION and run 5 select statements, one for each column in your table. It would look something like this:

SELECT right FROM answers
UNION
SELECT wrong1 FROM answers
UNION
SELECT wrong2 FROM answers
UNION
SELECT wrong3 FROM answers
UNION
SELECT wrong4 FROM answers

This will give you a single list containing all the answers. You'll still have duplicates though if you have multiple copies of the same answer within a single column.

Answer 2

Columns of "right, wrong1, wrong2, wrong3, wrong4" mean that you have a mis-designed database. In general, a number or letter suffix on a column name should be a red flag to rethink the problem.

As you observed, your design required you to hack around to get a solution to a typical data reduction problem.