Table: vuelta_2003
Columns: stage
winner
general_classification
points_classification
mountains_classification
combination_classification
team_classification

Question: How many combination classifications have the winner as Erik Zabel and a points classification as Alessandro Petacchi
SQL: SELECT COUNT("combination_classification") FROM vuelta_2003 WHERE "points_classification" = 'Alessandro Petacchi' AND "winner" = 'Erik Zabel'

Question: If winner is alejandro Valverde and the points Classification is by Erik Zabel, who is the mountain classification?
SQL: SELECT "mountains_classification" FROM vuelta_2003 WHERE "winner" = 'Alejandro Valverde' AND "points_classification" = 'Erik Zabel'

Question: How many teams have a combination classification of Alejandro Valverde and a Points classification of Alessandro Petacchi?
SQL: SELECT COUNT("team_classification") FROM vuelta_2003 WHERE "combination_classification" = 'Alejandro Valverde' AND "points_classification" = 'Alessandro Petacchi'