Return鍵和JSON字符串從SQL 2016查詢

Question

使用SQL 2016 JSON內置函數

表：用戶 列（ID INT，姓VARCHAR（50），姓氏VARCHAR（50）

數據 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

期望的結果 - >臨時表

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

嘗試使用：

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

Answer 1

與交叉的協助申領

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

這種形式可能會比使用交叉在某些情況下應用更具可讀性。
在我嘗試過的情況下，執行計劃總是相同的，但是在任何給定的情況下，執行計劃可能都會比另一方執行得更好。

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