Return all possible combinations of values on columns in SQL

Question

How do I return a list of all combinations of values in 2 columns so they are new rows in T-SQL?

e.g.

Col1, Col2
----  ----
1     2
1     4
1     5
<         


        

Answer 1

I was looking for something that would do this using only the SQL available to Microsoft Access 2016. I ended up figuring out something that others may find useful. This code utilizes CROSS JOIN so I found that it is necessary to split the two columns into two separate tables (each with one column). The AND statement forces one column to be less than the other, thereby eliminating any repetitive 1-2, 2-1 sort of occurrences.

SELECT DISTINCT Table1.Column1, Table2.Column1
FROM Table1, Table2
WHERE Table1.Column1 <> Table2.Column1
AND Table2.Column1 < Table1.Column1;