How to bulk update a records with value incremented - mysql

Question

I have over 1100+ records in my people (table) and i would like to filter those who are under a specific place (table) record and would update a newly inserted column value named people_identifier_num of people table.
Place table
id name desc
1 Place 1 some description.
2 Place 2 some description..
3 Place 3 some description...
People table
id name place_id people_identifier_num
1 People 1 1 null
2 People 2 1 null
3 People 3 2 null
4 People 4 2 null
5 People 5 2 null
6 People 6 2 null
7 People 7 3 null
... ... ... ....
1100 People 1100 2 null
Now i would like to assign a pin (people_identifier_num) to every person that belongs to a particular place which begin with value 1 and so on..
E.g.
id name place_id people_identifier_num
3 People 3 2 1
4 People 4 2 2
5 People 5 2 3
6 People 6 2 4
... ... ... ....
E.g.
id name place_id people_identifier_num
1 People 1 1 1
2 People 2 1 2
... ... ... ....
My current solution is to filter people by place and sort it by name alphabetically. However how can we write a SQL script that loop each filtered record and assign the pin value starting from 1 and so on?

Answer 1

You can use rank query to assign pin no. to each people according to their place
update people
join (
select p.id,place_id,name,
case when #place = place_id then #row:= #row +1 else #row:= 1 end rank,
#place:= place_id
from (
select * from people,(select #place:=null,#row:=1) t order by place_id,name
) p
) p1
using(place_id,name)
set people_identifier_num = p1.rank;
Demo