mysqldump insert data to exists table
If you can rebuild the x.sql, run mysqldump with suitable option such as --no-drop-tables, --no-creates (or whatever they are).  Then look at the dump file to make sure there are no surprises in it.

If you can't rebuild x.sql, then edit it to get rid of drops/creates/etc.

If there are no USE statements in x.sql, you can say mysql ... new_db &lt; x.sql (after doing CREATE DATABASE new_sql).  Then play SQL games to copy the data from new_db.foo to old_db.foo.  (Provide more details if you need help in this area.)