Getting emails from one table for another

[J j]

Hello,

I have 2 MySQL tables.

The first has as its structure:

id
custid
emails

The second is as follows:

id
custid
agentid
emails (this is what needs to be filled)


The 'emails' field in the second table is empty and I need to fill it. Obviously the field in common for both tables to do this is custid.

So I would need a query to check all the custid rows in the second table and if there is a corresponding email in the first table then it puts it in the second table emails field.

Hope this is clear.

Thanks for any guidance.

Regards