When querying relational tables in Big Query you might want to grab all the columns except a couple. I’ve run into this a few times where I want all the data from two joined tables, but I don’t want the created_at, updated_at columns that they both contain. Big Query will throw an error saying you can’t have duplicate columns. This can be fixed using EXCEPT

SELECT A.*, B.* EXCEPT (created_at, updated_at)
FROM A
LEFT JOIN B
ON a.id = b.a_id

Big Query SQL Query Syntax Reference