Find WordPress posts that are missing a specific custom field/postmeta

find-missing-postmeta.sql

SELECT *
FROM wp_posts
WHERE
	post_type = "ycd_individual" AND
	post_status = "publish" AND
	ID NOT IN (
		SELECT wp.ID
		FROM wp_posts wp
		LEFT JOIN wp_postmeta pm ON wp.ID = pm.post_id
		WHERE
			pm.meta_key = "yoko_directory_email_address" AND
			pm.meta_value != "" AND
			wp.post_type = "ycd_individual" AND
			wp.post_status = "publish"
	)
;