SQL to see what membership subscriptions are expiring for sending mail

Hi,

I currently have a subscription that starts with a trial period and then turns into a standard membership (free). They will have the option to upgrade to paid premium version.

When the subscription moves from trial period (trial premium level) to a standard, I have emails that would get sent out. This isn't happening, although I will get new signups when a test user registers.

The trial sub has :
premium level access for Finite days for $0.00.
then goes into:
standard level access for Indefinite for 1 year for $0.00. I've also tried Serial for 1 year.

Should the above flow trigger an expiration emeail when moving from premium access level to standard?

Mail is setup correctly as I'm able to get mail from "send me" on /wp-admin/admin.php?page=membershipcommunication&msg=12

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Is there a sql that I can use to see what memberships are expiring? I can change the dates till expiry as needed.

Is there a history of when crons run and what process was run?

Thanks,
Van