SELECT COUNT(*) FROM invoices WHERE billing_city  =  "Chicago" AND billing_state  =  "IL";
How many invoices were billed from Chicago, IL?
SELECT COUNT ( * ) FROM invoices WHERE billing_city = `` Chicago '' AND billing_state = `` IL '' ;
select count ( * ) from invoices where billing_city = value and billing_state = value
How many invoices were billed from Chicago , IL ?