sql - Row_Number Date Range -

i'm trying fill in table has personid appointment date, , whether or not follow call made after visit.

tbl_appt

    personid     appt_date     1            1/1/2016     1            1/3/2016     1            1/9/2016     1            1/31/2016 

tbl_call

    personid     call_date     1            1/5/2016     1            2/1/2016 

desired table: tbl_followup

    personid     appt_date   follow_up_flag     1            1/1/2016    n     1            1/3/2016    y     1            1/9/2016    n     1            1/31/2016   y 

the tbl_followup.follow_up_flag = y when tbl_call.call_date > tbl_appt.appt_date , before next appt.

i assume use row_number/partition, these functions allude me (see prior posts).

thanks in advance!

not extremely trivial, assuming have access window functions such row_number, here's option using lead , outer join:

select a.personid, a.appt_date,     case when c.personid null 'n' else 'y'      end follow_up_flag (       select personid,          appt_date,          lead(appt_date) on (partition personid order appt_date) next_appt_date       tbl_appt ) left join tbl_call c on c.personid = a.personid ,              c.call_date > a.appt_date ,              (c.call_date < a.next_appt_date or a.next_appt_date null) order a.appt_date