Table: us_gpw_1977
Columns: driver
constructor
laps
time_retired
grid

Question: How many laps did gunnar nilsson drive?
SQL: SELECT SUM("laps") FROM us_gpw_1977 WHERE "driver" = 'gunnar nilsson'

Question: Who built james hunt's car that went 79 laps?
SQL: SELECT "constructor" FROM us_gpw_1977 WHERE "laps" = 79 AND "driver" = 'james hunt'