Mysql：使用来自不同 table/column 的值更新 json 列

Question

我一直在尝试将 location table 中的下方 neighbors column 更新为 json 对象，如下所示，但无法以任何方式使其接近工作。对查询语法有什么想法吗？

原文table:

location
---------------
id  name  neighbors
1   loc1
2   loc2
3   loc3
4   loc4
5   loc5

nearby (this is join table where place & nextdoor refer to location.id)

nearby
-------------------
place   nextdoor    distance    group
1       2           500m         g1
1       3           900m         g1
2       1           500m         g3
2       3           100m         g4
2       4           80m          g4

预计更新后：

location
---------------
id  name  neighbors
1   loc1  {"g1":[{"name":"loc2", "distance":"500m"},{"name":"loc3", "distance":"900m"}]}
2   loc2  {"g3":[{"name":"loc1", "distance":"500m"}],"g4":[{"name":"loc3", "distance":"100m"},{"name":"loc4", "distance":"80m"}]}
3   loc3
4   loc4
5   loc5

Answer 1

试一试。它在 MySQL 8 上进行了测试。我将其分解为多个步骤，这样您就可以一个接一个地测试每个 CTE，看看它们是如何结合在一起的。

表格

create table location (id int, name varchar(10), neighbors json);
insert into location (id, name) values
(1, 'loc1'), (2, 'loc2'), (3, 'loc3'), (4, 'loc4'), (5, 'loc5');

create table nearby (place int, nextdoor int, distance varchar(10), mygroup varchar(10));
insert into nearby values
(1, 2, '500m', 'g1'), (1, 3, '900m', 'g1'),
(2, 1, '500m', 'g3'), (2, 3, '100m', 'g4'), (2, 4, '80m', 'g4');

更新查询

with flatten_neighbor as (
    select nn.place, nn.name, l.name as nextdoorname, nn.distance, nn.mygroup
    from (
        select l.id, l.name, n.place, n.nextdoor, n.distance, n.mygroup
        from location l
        join nearby n on n.place = l.id
    ) nn
    join location l on l.id = nn.nextdoor
),
obj_by_place as (
    select *, json_object('name', nextdoorname, 'distance', distance) as jo 
    from flatten_neighbor
),
concat_obj as (
    select place, mygroup, concat('[', group_concat(jo), ']') as jason
    from obj_by_place group by place, mygroup
),
final as (
    select place, json_objectagg(mygroup, jason) stuff
    from concat_obj group by place
)
update location l join final f on l.id = f.place set l.neighbors = f.stuff;

结果

id | name | neighbors                                                                                                                                                   
-: | :--- | :-----------------------------------------------------------------------------------------------------------------------------------------------------------
 1 | loc1 | {"g1": "[{\"name\": \"loc2\", \"distance\": \"500m\"},{\"name\": \"loc3\", \"distance\": \"900m\"}]"}                                                       
 2 | loc2 | {"g3": "[{\"name\": \"loc1\", \"distance\": \"500m\"}]", "g4": "[{\"name\": \"loc3\", \"distance\": \"100m\"},{\"name\": \"loc4\", \"distance\": \"80m\"}]"}
 3 | loc3 | null                                                                                                                                                        
 4 | loc4 | null                                                                                                                                                        
 5 | loc5 | null

例子

https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=789fb79d10b745414ca7270a5a6ef004

更新后的另一个示例 json_extract。

https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=fe651372ca754cc05eab842d6fced9a3

Mysql：使用来自不同 table/column 的值更新 json 列

Mysql: Update json column with values from different table/column

mysql

sql

mysql-json

表格

更新查询

结果

例子