Using a CASE statement to change the value of a new BigQuery column based finding one specific entry inside a PARTITION

Question

I trying to write some case statements which might change the value of all entries in the call if a particular condition is satisfied INSIDE the partition. Here is the specific

Answer 1

It is entirely possible that this could be done with a smart usage of analytics functions, but my SQL-fu isn't up to it. That said, it sounds like what you want is achievable with a simple JOIN statement. Let's say your current query is called Q (you could even save this as a view to make it easier).

Run

SELECT t1.*, t2.has_some_property
FROM Q AS t1
LEFT OUTER JOIN (
  SELECT unique_visit_id, 1 as has_some_property
  FROM Q 
  WHERE (REGEXP_MATCH(lagged, ...) 
      AND REGEXP_MATCH(hits.page.pagePath))
  GROUP BY unique_visit_id
  ) AS t2
ON t1.unique_visit_id == t2.unique_visit_id

Answer 2

If you are looking for avoiding joins, you can use an aggregated function with Over. something like:

Max(If((Your Condition here),Your value here, Null)) Over( Partition By Your_Partition)

the window functions used to had some performance issues that should have been improved recently. My experience with BQ drives me to prefer Jordan's Join suggestion. But hey, its a fun riddle...