Database: real_estate_rentals
Question: What are the ids of users who have only made one search, and what are their category codes?
SQL:
SELECT T1.user_category_code ,  T1.user_id FROM Users AS T1 JOIN User_Searches AS T2 ON T1.user_id  =  T2.user_id GROUP BY T1.user_id HAVING count(*)  =  1;