asked on

Basic math in MS SQL stored procedure across three tables

I'm trying to do some very basic math in MS SQL by using one stored procedure to SUM the value of a column in Table_A, then divide the SUM from Table_A by the page view total from Table_B - and UPDATE the value in Table_C.

Basically I'm trying to work out the eCPC for a lead generating site on a page view basis (so every time a user visits a profile the eCPC is updated against the SUM of leads generated).

val = common denominator across all three tables

So step 1 is:
SELECT SUM(lead_value) as lead_sum FROM Table_A WHERE camp_id='val'

Step 2:
SELECT page_views FROM Table_B WHERE camp_id='val'

Step 3:
new_eCPC = lead_sum / page_views

Step 4:
UPDATE Table_C SET lead_eCPC='new_eCPC' WHERE camp_id='val'

Now I can easilly do this in ASP, but I have to execute an SQL script three times to do this - which I believe is terribily inefficient as I want it to happen each time a profile is viewed.

Can someone please help we write a stored procedure for this so I only have to execute it once on each profile view?

Many Thanks!

C

Anthony Perkins

Something like this perhaps:

U PDATE  c
SET     lead_eCPC = a.lead_sum / b.page_views
FROM    Table_C c
        INNER JOIN (SELECT  SUM(lead_value) lead_sum
                    FROM    Table_A
                    WHERE   camp_id = 'val'
                   ) a ON c.camp_id = a.camp_id
        INNER JOIN Table_B b ON c.camp_id = b.camp_id

Open in new window

SOLUTION

Om Prakash

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

SOLUTION

udaydidigam

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

ASKER CERTIFIED SOLUTION

DerZauberer

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

BestAviation

ASKER

That is brilliant! Thanks very much guys - I don't use stored procedures very often so wasn't aware you could declare variables that easilly and execute multiple lines.

Anthony Perkins

Strange choice. Multiple SELECT statements over a single UPDATE statement? Obviously performance is not important to you.