Which campuses are in Northridge, Los Angeles?
select campus from campuses where location = "Northridge" and county = "Los Angeles"
How many are there?
select count(*) from campuses where location = "Northridge" and county = "Los Angeles"
How about the number of campuses that are in San Francisco, San Francisco?
select count(*) from campuses where location = "San Francisco" and county = "San Francisco"
Please add them.
select count(*) from (select campus from campuses where location = "Northridge" and county = "Los Angeles" union select campus from campuses where location = "San Francisco" and county = "San Francisco")
Show the names of the campuses.
select campus from campuses where location = "Northridge" and county = "Los Angeles" union select campus from campuses where location = "San Francisco" and county = "San Francisco"