RUBY - OCI8, Why doesn't a complex SQL query work?

Question

ruby

Hello everyone, when connecting to the database cursor = connection.parse("Complex SQL query"), the cursor is empty, i.e. as if the query failed. What could be the problem?
Everything is fine with the query, it directly gives the data that is needed.

With a simple SQL query, it works fine.

Answer 1

It's hard to tell without having the dataset itself.
Maybe there are no matches for the given REGEXP_SUBSTR pattern. Try first to search with REGEXP_SUBSTR for specific lines with a simple query, without JOIN, using WHERE REGEXP_LIKE. If they are under the given expression, then the reason is different.