Hello,
I'm trying to join two columns from different tables using LIKE, see the query below, I would expect the query should return nothing if there is no match in the join, this is not the case when there is null values in one of the columns, it still return data!!!
SELECT A.EDC, R.EDC_CODES
FROM RESULTS R
INNER join EDC_T A on A.EDC like ('%' || R.EDC_CODES ||'%');
i know for sure i have data in A.EDC(no nulls in this column) and there are possible null values in R.EDC_CODES, i know using nvl could solve it, but wondering why the query return data the way it written, in another words the query should exclude any data LIKE NULL but it is not, see what it return, those two columns used in the join?
thanks!