T-SQL OPENJSON路徑變量

Question

declare @Path as nvarchar(100) 
set @path = '$.path.to."sub-object"' 

DECLARE @json NVARCHAR(4000) = N'{ 
     "path": { 
      "to":{ 
       "sub-object":["en-GB", "en-UK","de-AT","es-AR","sr-Cyrl"] 
       } 
       } 
}'; 

SELECT [key], value 
FROM OPENJSON(@json, @Path) 

我得到錯誤：

Incorrect syntax near '@Path'.

如何聲明@path，我可以改變它。

Answer 1

有趣的是，你看到你正在關注這個鏈接：https://docs.microsoft.com/en-us/sql/t-sql/functions/openjson-transact-sql。

DECLARE @json VARCHAR(4000) = N'{ 
     "path": { 
      "to":{ 
       "sub-object":["en-GB", "en-UK","de-AT","es-AR","sr-Cyrl"] 
       } 
       } 
}'; 

SELECT [key], value 
FROM OPENJSON(@json, '$.path.to."sub-object"') 

當你做出改變一個變量的引用它不：

時在線完成這個工作

declare @Path as nvarchar(128) = '$.path.to."sub-object"' 

DECLARE @json nVARCHAR(4000) = N'{ 
     "path": { 
      "to":{ 
       "sub-object":["en-GB", "en-UK","de-AT","es-AR","sr-Cyrl"] 
       } 
       } 
}'; 

SELECT [key], value 
FROM OPENJSON(@json, @Path) 

更新了黑客的一種，但它的工作原理

declare @Path as nvarchar(128) = '$.path.to."sub-object"' 

DECLARE @json nVARCHAR(4000) = N'{ 
     "path": { 
      "to":{ 
       "sub-object":["en-GB", "en-UK","de-AT","es-AR","sr-Cyrl"] 
       } 
       } 
}'; 

DECLARE @SQL NVARCHAR(MAX) = 
'SELECT [key], value 
FROM OPENJSON(''' + @json + ''', ''' + @Path + ''')' 

EXEC sp_executesql @Sql 

Answer 2

將路徑作爲變量傳遞給OPENJSON可從SQL Server 2017（又名vNext）：

In SQL Server 2017 and in Azure SQL Database, you can provide a variable as the value of path.

declare @Path as nvarchar(100) 
set @path = '$.path.to."sub-object"' 

DECLARE @json NVARCHAR(4000) = N'{ 
     "path": { 
      "to":{ 
       "sub-object":["en-GB", "en-UK","de-AT","es-AR","sr-Cyrl"] 
       } 
       } 
}'; 

SELECT [key], value 
FROM OPENJSON(@json, @Path); 

DbFiddle Demo