CREATE TABLE table_204_947 (id NUMBER, "week" NUMBER, "date" CLOB, "opponent" CLOB, "result" CLOB, "attendance" NUMBER)

how many opponents were played twice that season ?
SELECT COUNT(*) FROM (SELECT "opponent" FROM table_204_947 GROUP BY "opponent" HAVING COUNT(*) = 2)
WITH "cte" AS (SELECT 1 AS "_" FROM "table_204_947" GROUP BY "opponent" HAVING COUNT(*) = 2) SELECT COUNT(*) FROM "cte" "cte"