Escape character in source query?

Hi, I have a SQL query that works perfectly in Oracle SQL Developer. Here is a condition I applied in SQL to eliminate a batch of extraneous rows. and upper(ou_code) not like ('A\_%')

In order for the condition to work correctly, excluding the right rows, but not exluding others, I needed to escape the underscore. The condition is actually based on this text: A_

When I ported the query into Power Bi Desktop, the condition is not being applied. In other words, rows that include A_ in the relevant field are NOT excluded in Power Bi.

When I remove the backshash escape character in the query sopurce in Power Bi, I have the same issue as in Oracle SQL developer, that caused me to use the SQL escape chracter.

So, what escape character should I use in this source query in Power Bi?

Thank you for any suggestions.