Context: CREATE TABLE room (blockfloor VARCHAR, blockcode VARCHAR); CREATE TABLE BLOCK (blockcode VARCHAR, blockfloor VARCHAR)
Question: Find the number of rooms for different block code?
Answer: SELECT COUNT(*), T1.blockcode FROM BLOCK AS T1 JOIN room AS T2 ON T1.blockfloor = T2.blockfloor AND T1.blockcode = T2.blockcode GROUP BY T1.blockcode