CREATE TABLE table_74629 ("Club" TEXT, "Total points" TEXT, "Bonus points" TEXT, "Match points" TEXT, "Games" TEXT, "Drawn" TEXT, "Lost" TEXT, "Points for" TEXT, "Points against" TEXT, "Diff" TEXT)

What is the diff for a club that has a value of 662 for points for?
SELECT "Diff" FROM table_74629 WHERE "Points for" = '662'
SELECT "Diff" FROM "table_74629" WHERE "Points for" = '662'