MySQL SELECT DISTINCT multiple columns

Question

Let\'s say I have columns a, b c, d in a table in a MySQL database. What I\'m trying to do is to select the distinct values of ALL of these 4 columns in my tabl

Answer 1

Taking a guess at the results you want so maybe this is the query you want then

SELECT DISTINCT a FROM my_table
UNION 
SELECT DISTINCT b FROM my_table
UNION
SELECT DISTINCT c FROM my_table
UNION
SELECT DISTINCT d FROM my_table