SQL “Join” on null values

Question

For reasons beyond my control, I need to join two tables and I need null values to match. The best option I could think of was to spit out a UUID and use that as my comparis

Answer 1

For this sort of task Oracle internally uses an undocumented function sys_op_map_nonnull(), where your query would become:

SELECT *
FROM T1 JOIN T2 ON sys_op_map_nonnull(T1.SOMECOL) = sys_op_map_nonnull(T2.SOMECOL)

Undocumented, so be careful if you go this route.