SQL query to give all non-member WP users level 1 with a specific start and end date set.

insert_members.sql

#give all non-member WP users level 1 with a specific start and end date set
#change the level (1) below and start (2017-01-01) and end (2017-12-31) dates below to per your needs
INSERT INTO wp_pmpro_memberships_users (user_id, membership_id, status, startdate, enddate) 
SELECT 
	u.ID,  			#ID from wp_users table
	1, 			#id of the level to give users
	'active', 		#status to give users
	'2017-01-01', 		#start date in YYYY-MM-DD format
	'2017-12-31' 		#end date in YYYY-MM-DD format, use '' for auto-recurring/no end date
FROM wp_users u 
	LEFT JOIN wp_pmpro_memberships_users mu 
		ON u.ID = mu.user_id 
		AND status = 'active' 
WHERE mu.id IS NULL

This recipe is included in the blog post on "Database Script: Apply a membership level to all users without a level" at Paid Memberships Pro here: https://www.paidmembershipspro.com/database-script-apply-membership-level-users-without-level/