Home/ Questions/Q 6014739
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-23T02:44:11+00:00

Imagine a table : CUST_PROMO (customer_id,PROMOTION) which is used as a mapping between every

  • 0

Imagine a table :

CUST_PROMO (customer_id,PROMOTION) which is used as a mapping between every promotion that customer have received. 

select promotion, count(customer_id) as promo_size
from CUST_PROMO
group by promotion

This gets us the total number of customers in each promotion.

Now, we’ve got CUSTOMER (customer_id, PROMO_RESPONDED,PROMO_PURCHASED), which lists the customer and which promotion got the customer to respond, and which got them to purchase. 

select PROMO_RESPONDED, count(customer_id) as promo_responded 
from CUSTOMER
group by PROMO_RESPONDED

select PROMO_PURCHASED,count(customer_id) as promo_responded 
from CUSTOMER 
group by PROMO_PURCHASED

This is all very self-explanatory; now I’ve got the number of people for whom each promo was successful.

But; what I’d like to end up with is [in CSV form]

PROMOTION,PROMO_SIZE,PROMO_RESPONDED,PROMO_PURCHASED,PROMO_RESPSUCCESSRATE,blah

1,100,12,5,12%,...
2,200,23,14,11.5%,...

I have no idea how to do this. I can UNION the three queries above; but that doesn’t actually result in what I want. I thought about creating an in-memory table, inserting in each promo value and then doing an update statement with a join against it to set the values each — but that’s pretty messy; and requires a new UPDATE statement for each table/select statement. I could also make a temp table per result set and then join them together; but really; who wants to do that?

I can’t think of any way of joining this data that makes any sense; since I’m dealing with aggregates.

So, at best, I need a function that, like UNION, will combine result sets, but will actually combine like columns on a key and ADD those columns rather than union which adds rows. The description makes it sound like a JOIN; but I can’t see that working.

Thanks for the help!

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team
    SELECT
  cp.promotion,
  PROMO_SIZE = COUNT(*),
  PROMO_RESPONDED = COUNT(c1.customer_id),
  PROMO_PURCHASED = COUNT(c2.customer_id),
  PROMO_RESPSUCCESSRATE = COUNT(c1.customer_id) * 100.0 / COUNT(*)
FROM CUST_PROMO cp
  LEFT JOIN CUSTOMER c1
    ON cp.customer_id = c1.customer_id AND cp.promotion = c1.PROMO_RESPONDED
  LEFT JOIN CUSTOMER c2
    ON cp.customer_id = c2.customer_id AND cp.promotion = c2.PROMO_PURCHASED
GROUP BY cp.promotion
    • 0