BigQuery Standard SQL - 查询具有相同架构的 3 个不同表。 如何添加每行来自哪个表的列？

Question

Say I have 3 tables containing clothing brands from - walmart, target, amazon. I make a new table and query * from each table into this new table. I want to know which company (walmart, target or amazon) each of these items is from. How would I go about doing this in BigQuery?

Thank you.

Answer 1

Use below approach

select *, 'table1' as source from table1 union all
select *, 'table2' from table2 union all
select *, 'table3' from table3