Hi @sieusaopolo15 ,

Here's a few hidden rules that will make your life easier once you know them:

• Your "Where" clauses may only refer to view tables that were evaluated prior to the currently running view table

• The evaluation order is determined by the "Ordering" (lower = earlier), but there's a catch!

• Left-joins always run last, regardless of the order value. They are basically happening in an entirely different phase that comes after the primary phase

• Ordering is still used with left-joins, but only to determine execution order relative to other left-joins

• Because left joins run last, view tables that are not left-joined may never refer to left-joined view tables

You can refer to below links for example : https://www.servicenow.com/community/itsm-forum/database-view-left-join-help/m-p/644370

https://www.servicenow.com/docs/bundle/yokohama-platform-administration/page/use/reporting/task/exam...

And video : https://www.servicenow.com/community/in-other-news/database-views-left-joins-and-filters-video/ba-p/...