How to build a table based on existing ones?

Question

MySQL

There is such a structure of tables, how to build a new table with supplier numbers and pairs of part numbers, such that some supplier supplies both specified parts. At the same time, pairs of the form 1 and 2, as well as 2 and 1, are considered the same?

Answer 1

If I understand correctly, then all possible pairs of parts that are supplied by one supplier

SELECT t1.Snum, t1.Pnum, t2.Pnum FROM `spj` as t1
join spj as t2 on t1.Snum = t2.Snum and t1.Pnum != t2.Pnum