Step 1 - Understanding The DCM Data

The tagging scheme of the site is as below

And this is where we will be looking for the U3 tag

#standardSQL
SELECT
  *
FROM
  `MRKL_DCM.p_activity_8066`
WHERE
  Other_Data LIKE "%u3=%"
  AND Advertiser_ID = '5218710'
LIMIT
  100