CREATE TABLE table_70493 ("Venue" TEXT, "City" TEXT, "Tickets Sold / Available" TEXT, "Gross Revenue  ( 1986 ) " TEXT, "Gross Revenue  ( 2011 ) " TEXT)

How many tickets were there sold/available in Barcelona?
SELECT "Tickets Sold / Available" FROM table_70493 WHERE "City" = 'barcelona'
SELECT "Tickets Sold / Available" FROM "table_70493" WHERE "City" = 'barcelona'