Table: alex_caffi_1986
Columns: year
entrant
chassis
engine
points

Question: What is the chassis after 1991?
SQL: SELECT "chassis" FROM alex_caffi_1986 WHERE "year" > 1991

Question: What are the average points after 1992?
SQL: SELECT AVG("points") FROM alex_caffi_1986 WHERE "year" > 1992

Question: What is the sum of points in 1991, for footwork a11c chassis?
SQL: SELECT SUM("points") FROM alex_caffi_1986 WHERE "year" = 1991 AND "chassis" = 'footwork a11c'