Find the number of rooms located on each block floor.
create table room (blockfloor varchar, blockcode varchar, PRIMARY KEY (blockfloor)); create table block (blockfloor varchar, blockcode varchar, PRIMARY KEY (blockfloor))
select count(*), t1.blockfloor from block as t1 join room as t2 on t1.blockfloor = t2.blockfloor and t1.blockcode = t2.blockcode group by t1.blockfloor