How many years was Louis Armstrong performing?
CREATE TABLE table_name_51 (year VARCHAR, performer_s_ VARCHAR)
SELECT COUNT(year) FROM table_name_51 WHERE performer_s_ = "louis armstrong"
### Context: CREATE TABLE table_name_51 (year VARCHAR, performer_s_ VARCHAR) ### Question: How many years was Louis Armstrong performing? ### Answer: SELECT COUNT(year) FROM table_name_51 WHERE performer_s_ = "louis armstrong"