CREATE TABLE table_204_929 (id NUMBER, "location" CLOB, "name of mill and\ grid reference" CLOB, "type" CLOB, "maps" CLOB, "first mention\ or built" CLOB, "last mention\ or demise" NUMBER)

how many locations have or had at least 2 windmills ?
SELECT COUNT(*) FROM (SELECT "location" FROM table_204_929 GROUP BY "location" HAVING COUNT(*) >= 2)
WITH "cte" AS (SELECT 1 AS "_" FROM "table_204_929" GROUP BY "location" HAVING COUNT(*) >= 2) SELECT COUNT(*) FROM "cte" "cte"