Hi, i don't know if this forum is totally or partially french, so i prefer write this in english. I am working with Vertcia Hp SQL.
So i expose you my problem. I work in a firm and i need to make a SQL request on a database, where i have for each customer a unique login. But this database represent subscriptions and each customer can have several rows (subscriptions) in the database. For customers who have several rows (>2) i want to lineary regress the price of each subscription in function of the date of beginning of each rows (or subscription). I precise that i order dates of beginning of each cotumer.
But my problem is that some of my results of the regr_slope are "NULL". But for this "NULL", customers have prices of subscriptions not "NULL". Can someone help me on this problem ?
Did Someone have the same problem like me ?