CREATE TABLE table_39192 ("Round" TEXT, "Date" TEXT, "Opponent" TEXT, "Venue" TEXT, "Result" TEXT, "Attendance" FLOAT)

How much Attendance has an Opponent of oxford united?
SELECT SUM("Attendance") FROM table_39192 WHERE "Opponent" = 'oxford united'
SELECT SUM("Attendance") FROM "table_39192" WHERE "Opponent" = 'oxford united'