CREATE TABLE table_3147 ("Result" CLOB, "Date" CLOB, "Race" CLOB, "Venue" CLOB, "Group" CLOB, "Distance" CLOB, "Weight  ( kg ) " CLOB, "Jockey" CLOB, "Winner/2nd" CLOB)

The MacKinnon Stakes races took place on how many venues?
SELECT COUNT("Venue") FROM table_3147 WHERE "Race" = 'Mackinnon Stakes'
SELECT COUNT("Venue") FROM "table_3147" WHERE "Race" = 'Mackinnon Stakes'