/*TO GET EACH CUSTOMER'S FIRST ORDER*/ select distinct first_value(order_id) over(partition by customer_id order by order_date) as firstorder from Delivery; #Its a window function that retrieves first value in an ordered partition of data
/*TO GET EACH CUSTOMER'S FIRST ORDER*/ select distinct first_value(order_id) over(partition by customer_id order by order_date) as firstorder from Delivery; #Its a window function that retrieves first value in an ordered partition of data