42P01: undefined_table

What does it mean?

The table (or view) referenced in the query does not exist or cannot be found in the search_path.

Why does it happen?

The table really does not exist, it is in another schema that is not in the search_path, a typo/case error in the table name, a case mismatch with quoted identifiers, or the object has not been created yet or was dropped.

How to fix it

Verify the table exists and its schema: SELECT schemaname, tablename FROM pg_tables WHERE tablename = 'my_table'. If it is in another schema, qualify it as schema.table or set the search_path: SET search_path TO app_schema, public. Remember that unquoted identifiers are folded to lowercase; if quotes were used at creation, reference it the same way.