CREATE TABLE table_19833 ("Stage" FLOAT, "Winner" TEXT, "General classification" TEXT, "Points classification" TEXT, "Mountains classification" TEXT, "Combination classification" TEXT, "Team classification" TEXT)

How many combination classifications have the winner as Erik Zabel and a points classification as Alessandro Petacchi
SELECT COUNT("Combination classification") FROM table_19833 WHERE "Points classification" = 'Alessandro Petacchi' AND "Winner" = 'Erik Zabel'
SELECT COUNT("Combination classification") FROM "table_19833" WHERE "Points classification" = 'Alessandro Petacchi' AND "Winner" = 'Erik Zabel'