What: The JOIN function is part of the FROM statement and connects databases together.
Why: The JOIN allows you to merge multiple databases together pulling similar records and fields into your query.
Overview of different JOINs:
There are many JOINs to consider, here are the top three that you most likely will use most often:
(1) INNER or JOIN: pulls in all records that match criteria in both databases.
(2) LEFT JOIN Match: pulls in all records that match criteria in both databases as well as all of the records in the first database.
(3) LEFT JOIN Dedupe: Excludes any records from the 2nd database that match the first database. This query is very helpful for deduping a database or list.
(A) You LEFT JOIN the second database to the first database.
(B) in the WHERE you add to only bring in records where the subscriber from the second database is null or not present
To find out more about all the different joins check out our SQL Cheat Sheet: https://handsonsfmc.com/query-cheat-sheet/ where you can see an excellent visual breakdown of the different JOINs.
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