Table: san_marino_gp_2001
Columns: driver
constructor
laps
time_retired
grid

Question: Who built michael schumacher's car that went under 31 laps?
SQL: SELECT "constructor" FROM san_marino_gp_2001 WHERE "laps" < 31 AND "driver" = 'michael schumacher'

Question: How many grids for heinz-harald frentzen with 61 laps?
SQL: SELECT COUNT("grid") FROM san_marino_gp_2001 WHERE "laps" = 61 AND "driver" = 'heinz-harald frentzen'