CREATE TABLE table_2560677_1 (artist_s_ VARCHAR2, start_date VARCHAR2)

How many artist(s) have a start date is 1966-12-12?
SELECT COUNT(artist_s_) FROM table_2560677_1 WHERE start_date = "1966-12-12"
SELECT COUNT("artist_s_") FROM "table_2560677_1" WHERE "1966-12-12" = "start_date"