Question

使用SQL 2016 JSON内置函数

表：用户列（ID int，FirstName varchar（50），LastName varchar（50）

数据 3009 Emily Manners 3010 Joanne Hernandez 3011 Kelly Kleiner 3012 Alexis Frederick 3013 Dietric Singleton 3018 Ashley Ely 3021 Jeralynn Campbell-Triplett 3026 Lauren Zinnerman 3027 Christopher Correa 3028 Stefanie MontalvoCruz

期望的结果 - ＆gt;临时表

ID       JSON_DATA        
3009    {"ID":3009,"FirstName":"Emily","LastName":"Manners"}
3010    {"ID":3010,"FirstName":"Joanne","LastName":"Hernandez"}

尝试使用：

SELECT
    [ID],
    [FirstName],
    [LastName]
FROM Emp
FOR JSON PATH, INCLUDE_NULL_VALUES, WITHOUT_ARRAY_WRAPPER

Answer 1

在CROSS APPLY

的帮助下

Declare @Emp table (ID int,FirstName varchar(50),LastName varchar(50))
Insert into @Emp values
(3009,'Emily' ,'Manners'),
(3010,'Joanne','Hernandez'),
(3011,'Kelly' ,'Kleiner')

Select A.ID
      ,B.JSON_Data
 From @Emp A
 Cross Apply (
               Select JSON_Data = (Select A.ID,A.FirstName,A.LastName FOR JSON PATH, INCLUDE_NULL_VALUES, WITHOUT_ARRAY_WRAPPER)
             ) B

返回

ID      JSON_Data
3009    {"ID":3009,"FirstName":"Emily","LastName":"Manners"}
3010    {"ID":3010,"FirstName":"Joanne","LastName":"Hernandez"}
3011    {"ID":3011,"FirstName":"Kelly","LastName":"Kleiner"}

Answer 2

在某些情况下，此表格可能比使用交叉申请更具可读性在我尝试过的情况下，执行计划总是相同的，但在任何特定情况下，执行计划可能比其他计划表现更好。

Declare @Emp table (ID int,FirstName varchar(50),LastName varchar(50))
Insert into @Emp values
(3009,'Emily' ,'Manners'),
(3010,'Joanne','Hernandez'),
(3011,'Kelly' ,'Kleiner')

Select A.ID
      ,(Select A.ID,A.FirstName,A.LastName 
           FOR JSON PATH, INCLUDE_NULL_VALUES, 
           WITHOUT_ARRAY_WRAPPER) AS JSON_Data
 From @Emp A

从SQL 2016查询

2 个答案: