Find the names of departments that are located in Houston.
SELECT t1.dname FROM department AS t1 JOIN dept_locations AS t2 ON t1.dnumber  =  t2.dnumber WHERE t2.dlocation  =  'Houston'
names of departments = SELECT t1.dname; located in Houston refers to WHERE t2.dlocation = 'Houston'; joining tables department and dept_locations on department number = JOIN department AS t1 JOIN dept_locations AS t2 ON t1.dnumber = t2.dnumber;