MySQL: Select Distinct from 2 different tables?

Question

I have 2 different tables that each have a column called product_type. How can I get the DISTINCT values of product_type across both tables? Just to clarify, if both tables have a product_type of "diamond" I only want it returned once. Basically as if both tables where combined and I selected distinct product_type from it.

Thanks!!

Answer 1

Note that the UNION clause returns unique values of the field, when you want it to return ALL the values you must use UNION ALL...

select product_type from table_a
union
product_type from table_b

Answer 2

Use a distinct with a subquery which contains a union

select distinct product_type from (
    select product_type from table 1
    union 
    select procut_type from table 2
) t

Answer 3

Use distinct and union:

select distinct product_type from table1
union
select distinct product_type from table2

The union will remove duplicates when combining the results.