The "not perl" line is (as others have mentioned) blurred.
A DBI or database related question will often require a SQL answer. Quite often the SQL will be completely unrelated to the specific perl problem/script, but it is still a relevant answer.
I often step in to add additional information relating to Sybase and/or MS-SQL database programming because it enhances the answers given previously, and expands the knowledge of the user asking the original question. That is, IMHO, a reasonable use of the Monastery.