SQL 服務器 JSON 文本格式不正確。 在 position 0 處發現意外字符

Question

許多人都有這個問題，但這通常是因為 JSON 不正確。 誰能告訴我為什么這不起作用。 我希望得到一個結果集：

ONE  FirstName LastName
1    John      Smith

Instead, I get an empty result set and the following error message in SSMS:

Msg 13609, Level 16, State 2, Line 20
JSON text is not properly formatted. Unexpected character 'J' is found at position 0.

DECLARE @IN_JSON NVARCHAR(MAX) = 
N'{
    "resume": {
    "mailAddress": {
      "sectionOrder": 10,
      "section": {
        "firstName": "John",
        "lastName": "Smith"
      }
    }
  }
}'


 
SELECT '1' AS [One],
       JSON_VALUE(a.value, '$.firstName') AS [FirstName],
       JSON_VALUE(a.value, '$.lastName') AS [LastName]
  FROM OPENJSON (@IN_JSON, '$.resume.mailAddress.section') AS a

Answer 1

由於您嘗試將JSON_VALUE() function 應用於非 JSON 值，因此這是錯誤的。 實際上，您已經可以使用OPENJSON()提取所需的列值，只需針對這種情況應用條件聚合，例如

SELECT '1' AS [One],
       MAX(CASE WHEN [key] = 'firstName' THEN value END) AS [FirstName],
       MAX(CASE WHEN [key] = 'lastName' THEN value END) AS [LastName]
  FROM OPENJSON (@IN_JSON, '$.resume.mailAddress.section') AS a

演示

Answer 2

   -- A colleague showed me the following  which works as well. And thank you again Barbaros for the very fast response.

DECLARE @IN_JSON NVARCHAR(MAX) = 
    N'{
        "resume": {
        "mailAddress": {
          "sectionOrder": 10,
          "section": {
            "firstName": "John",
            "lastName": "Smith"
          }
        }
      }
    }'
    
    SELECT '1' AS [One]
        , JSON_VALUE(@IN_JSON, '$.resume.mailAddress.section.firstName') AS [FirstName]
        , JSON_VALUE(@IN_JSON, '$.resume.mailAddress.section.lastName') AS [LastName]

-- Output result set:
-- One  FirstName   LastName
-- 1    John        Smith