If you’re reading this, you have likely just slammed your fist on your desk. The "420" class error is one of the most common—yet misunderstood—syntax exceptions in the SQL universe. Unlike a simple typo, the "unterminated" qualifier suggests that your database engine thinks your query is still waiting for more input.
Copy the exact SQL statement that failed. Do not try to debug it inside a massive application framework. Paste it directly into a database console (e.g., mysql -u root -p or psql ).
If you are using an ORM (Object-Relational Mapper) like Hibernate, Entity Framework, or a JDBC/ODBC driver, the driver is responsible for packaging your code into the database protocol.
When combined with the database is essentially saying: "I started reading your SQL command, but I never found the official end of it. I am stuck in a parsing limbo."