Question

我的people (table)中有超过1100条记录，我希望过滤特定place (table)记录下的记录，并更新名为people_identifier_num people的新插入列值{1}}表。

放置表格

id   name          desc
1    Place 1       some description.
2    Place 2       some description..
3    Place 3       some description...

人员表

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

现在我想将 pin（people_identifier_num）分配给属于以值1开头的特定地点的每个人，依此类推。

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
...    ...          ...            ....

我目前的解决方案是按地点过滤人员并按字母顺序对其进行排序。但是，我们如何编写一个循环每个已过滤记录的SQL脚本，并从1开始分配引脚值，依此类推？

Answer 1

您可以使用排名查询来分配引号。根据他们的位置给每个人

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

如何批量更新值增加

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