SQL：使用一列中的不同值来选择另一列中的所有对应的不同值

Question

Suppose I have a data set such as this:

ColA    ColB
====    ====
Foo     Green
Foo     Purple
Bar     Magenta
Bar     Green
Foo     Purple
Bar     Purple
Bar     Purple
Foo     Green
Bar     Green

I would like to query this data and return the below. Essentially, take all distinct values from ColA (Foo & Bar) and return all distinct values for EACH of them from ColB:

ColA    ColB
====    ====
Foo     Green
Foo     Purple
Bar     Magenta
Bar     Green
Bar     Purple

I know I'm overthinking this...but I can't seem to hammer it out...

Answer 1

Please use of of the below -

SELECT DISTINCT cola,colb FROM yourtableName

OR

SELECT cola,colb From yourtableName
GROUP BY cola,colb