Question

I am trying to build a select query that will essentially left join two tables and display one column from each table as a single column.

the table structure is similar to:

table a:

id, email

table b:

id, tablea_id, email

I am trying to get a single column of email and email (with no dupes or nulls ideally).

ideal results would be:

[e-mail]
[e-mail]
[e-mail]

and the email address that is returned could be from either a or b.

Maybe a union is what would work best, but I not able to figure out how to do a union on the second table based on the id of the first table.

When searching for a solution, perhaps my wording is bad, but I can’t find any examples.

thanks for any help.

Answer 1

It seems that you want something on the lines of this:

SELECT email
FROM TableA
UNION
SELECT B.email
FROM TableA A
JOIN TableB B
ON A.id = B.TableA_id