what is the sum of totaltk when yards is less than 0?
CREATE TABLE table_name_9 (totaltk INTEGER, yards INTEGER)
SELECT SUM(totaltk) FROM table_name_9 WHERE yards < 0
### Context: CREATE TABLE table_name_9 (totaltk INTEGER, yards INTEGER) ### Question: what is the sum of totaltk when yards is less than 0? ### Answer: SELECT SUM(totaltk) FROM table_name_9 WHERE yards < 0