PgSQL string is converted to array and associated with other tables, which are displayed in the original order after matching and splicing

Realization principle ：

1.unnest(string_to_array(mnc.email_user_id , ',')) String to array Turn into a row and then match

2.WITH ORDINALITY a(user_id, nr) This function is used to display subscripts , Easy to sort later

3. After matching, aggregate in the original order

The source data is shown in the red box below

  The effect you want to achieve is as follows （ In the same order ）

  Realized sql as follows

select
	string_agg(b.user_name || '(' || b.user_id || ')', ',')as emailUserName ,
	b.email_user_id
from
	(
	select
		su.user_name,
		su.user_id ,
		mnc.*
	from
		fas_mail_notification_config mnc,
		unnest(string_to_array(mnc.email_user_id , ','))with ordinality a(user_id,nr)
	left join sec_user su on a.user_id = su.user_id
	where
		mnc.delete_flg = 0
		and mnc.bg_id = '49bd50924c434556aca0193bcffb2dce'
		and mnc.business_type = '1'
	order by
		mnc.id,
		mnc.bg_id ,
		a.nr
      )b
group by
	b.id,
	b.bg_id,
	b.email_user_id