CREATE TABLE table_46273 ("Year" FLOAT, "Date" CLOB, "Winner" CLOB, "Result" CLOB, "Loser" CLOB, "Location" CLOB)

Which date had a year under 1988, loser of Philadelphia Eagles, location of Giants Stadium, and a result of 21-0?
SELECT "Date" FROM table_46273 WHERE "Year" < '1988' AND "Loser" = 'philadelphia eagles' AND "Location" = 'giants stadium' AND "Result" = '21-0'
SELECT "Date" FROM "table_46273" WHERE "Location" = 'giants stadium' AND "Loser" = 'philadelphia eagles' AND "Result" = '21-0' AND "Year" < '1988'