create table t1(ID int identity,name nvarchar(50),Chinese int ,Math int)
insert into t1 values ('张三',90,80),('李四',75,90),('王五',68,100)
select * from t1
select * from t1 for json auto
--查询结果
ID     name                        Chinese   Math
----------- -------------------------------------------------- ----------- -----------
1      张三                         90     80
2      李四                         75     90
3      王五                         68     100
--json 格式
[{"ID":1,"name":"张三","Chinese":90,"Math":80},{"ID":2,"name":"李四","Chinese":75,"Math":90},{"ID":3,"name":"王五","Chinese":68,"Math":100}]

select ID,
    name,
    Chinese as [Points.Chinese],
    Math as [Points.Math]
  from t1 for json path
--结果json
[
{"ID":1,"name":"张三","Points":{"Chinese":90,"Math":80}},
{"ID":2,"name":"李四","Points":{"Chinese":75,"Math":90}},
{"ID":3,"name":"王五","Points":{"Chinese":68,"Math":100}}
]

select ID,
    name,
    Chinese as [Points.Chinese],
    Math as [Points.Math]
  from t1 for json path,root('root') 
--返回的json结果
{"root":[
  {"ID":1,"name":"张三","Points":{"Chinese":90,"Math":80}},  {"ID":2,"name":"李四","Points":{"Chinese":75,"Math":90}},{"ID":3,"name":"王五","Points":{"Chinese":68,"Math":100}}]} 

insert into t1 values ('赵六',100,null)
select ID,
    name,
    Chinese as [Points.Chinese],
    Math as [Points.Math]
  from t1 
    where id in(3, 4)
  for json auto
--json的返回结果
[{"ID":3,"name":"王五","Points.Chinese":68,"Points.Math":100},{"ID":4,"name":"赵六","Points.Chinese":100}]

select ID,
    name,
    Chinese as [Points.Chinese],
    Math as [Points.Math]
  from t1 
    where id in(3, 4)
  for json auto, include_null_values
--json 的返回结果
[{"ID":3,"name":"王五","Points.Chinese":68,"Points.Math":100},{"ID":4,"name":"赵六","Points.Chinese":100,"Points.Math":null}]