使用JSON_VALUE访问SQL Server 2016中的JSON数组

Z时代
2024-01-10
分类：问答

使用新引入的JSON_VALUE函数访问json内的数组时，我陷入了困境。请考虑以下代码-

IF EXISTS(SELECT 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='JsonData')
    DROP TABLE JsonData;
go
CREATE TABLE JsonData(JsonData nvarchar(max));
DECLARE @SQL nvarchar(max);
DECLARE @Table AS TABLE(JsonPath VARCHAR(256));
INSERT INTO JsonData(JsonData)
VALUES(
'{
  "firstName": "John",
  "lastName" : "doe",
  "age"      : 26,
  "address"  : {
    "streetAddress": "naist street",
    "city"         : "Nara",
    "postalCode"   : "630-0192"
  },
  "phoneNumbers": [
    {
      "type"  : "iPhone",
      "number": "0123-4567-8888"
    },
    {
      "type"  : "home",
      "number": "0123-4567-8910"
    }
  ]
}')
INSERT INTO @Table
SELECT VALUE  FROM OPENJSON('{
"Path1":"$.firstName","Path2":"$.phoneNumbers[:1].number"
}') ;
SELECT  @SQL=(SELECT 'UNION SELECT '''+ CAST(JsonPath AS VARCHAR(256)) +''',JSON_VALUE(JsonData,'''+a.JsonPath+''')  
                    FROM JsonData a'                             
                    FROM @Table a       
        FOR XML PATH(''), TYPE)
    .value('.','NVARCHAR(MAX)')
FROM @Table t;
SELECT @SQL=RIGHT(@SQL,LEN(@SQL)-5)
PRINT @SQL
EXEC SP_EXECUTESQL @SQL;

在这里，如果我想访问特定的电话号码，则访问该节点的常规语法不起作用。在这种情况下，我遇到以下错误

JSON path is not properly formatted. Unexpected character ':' is found at position 15.

虽然当我在http://jsonpath.com上进行检查时，却能够检索值。SQL Server

2016是否使用某些不同的语法来访问JSON值？

回答：

要从phoneNumbers获取全部信息：

DECLARE @json nvarchar(max)=
    '{
      "firstName": "John",
      "lastName" : "doe",
      "age"      : 26,
      "address"  : {
        "streetAddress": "naist street",
        "city"         : "Nara",
        "postalCode"   : "630-0192"
      },
      "phoneNumbers": [
        {
          "type"  : "iPhone",
          "number": "0123-4567-8888"
        },
        {
          "type"  : "home",
          "number": "0123-4567-8910"
        }
      ]
    }'
    SELECT [Type], [Number]
    FROM OPENJSON( @json, '$.phoneNumbers' ) 
    WITH ([Type] NVARCHAR(25) '$.type', [Number] NVARCHAR(25) '$.number');