CREATE TABLE table_name_19 (date NUMBER, works_number VARCHAR2, builder VARCHAR2, number VARCHAR2)

Which Date has a Builder of alco schenectady, and a Number larger than 835, and Works number of 56566?
SELECT AVG(date) FROM table_name_19 WHERE builder = "alco schenectady" AND number > 835 AND works_number = 56566
SELECT AVG("date") FROM "table_name_19" WHERE "alco schenectady" = "builder" AND "number" > 835 AND "works_number" = 56566