Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations TouchToneTommy on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
-
Counting customers with special history in SQL
hello i've a CUSTOMERS table (customer_id) and a PURCHASES table (customer_id, purchase_date,purchase_id) I'm trying to count the number of customers who bought purchase_id = X and, in the 12 months before buying X, also bought at least twice purchase_id = Z. Any idea ? Thanks in advance Patrick
