OPENJSON - 无法查询嵌套元素

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【中文标题】OPENJSON - 无法查询嵌套元素【英文标题】：OPENJSON - Unable to query nested elements 【发布时间】：2019-05-13 23:23:36 【问题描述】：

我在使用 SQL Server 2016 中的 T-SQL OPENJSON 函数查询 JSON 文档的嵌套元素时遇到困难。我通读了 MSDN 文档 here 、 here 和 here 但还没有找到WITH 块的正确语法。我的列一直只返回一个空行。

任何人都可以协助修改 T-SQL 以实现这样的查询输出（如下）？

这里是json结构&空输出：

DECLARE @json NVARCHAR(MAX)
SET @json =  N'"meta":"total_record_count":4870,"total_pages":98,"current_page":97,"per_page":50,"companies":["id":"13463591","url":"https://api.mattermark.com/companies/13463591","company_name":"Modula4","domain":"modula4.com","id":"13531979","url":"https://api.mattermark.com/companies/13531979","company_name":"Rae Development Corp","domain":"raedevelopment.com","id":"13537660","url":"https://api.mattermark.com/companies/13537660","company_name":"jBASE","domain":"jbase.com","id":"13537769","url":"https://api.mattermark.com/companies/13537769","company_name":"D2Effects LLC","domain":"bitefx.com","id":"13537784","url":"https://api.mattermark.com/companies/13537784","company_name":"eSyncTraining","domain":"esynctraining.com","id":"13541751","url":"https://api.mattermark.com/companies/13541751","company_name":"Business Computing","domain":"bcinc.net","id":"13553270","url":"https://api.mattermark.com/companies/13553270","company_name":"KNIGHTLING INC.","domain":"knightling.com","id":"13560476","url":"https://api.mattermark.com/companies/13560476","company_name":"Netcentric systems","domain":"netcentricsystems.com","id":"13560643","url":"https://api.mattermark.com/companies/13560643","company_name":"Fortium Solutions, LLC","domain":"fortiumsolutions.com","id":"13561893","url":"https://api.mattermark.com/companies/13561893","company_name":"PMAC SERVICES INC","domain":"pmacservices.com","id":"13587256","url":"https://api.mattermark.com/companies/13587256","company_name":"Bayonet Inc.","domain":"mybayonet.com","id":"13590982","url":"https://api.mattermark.com/companies/13590982","company_name":"IQA","domain":"instrumentalqa.com","id":"13593143","url":"https://api.mattermark.com/companies/13593143","company_name":"Atech Consultants","domain":"atechconsultants.com","id":"13601156","url":"https://api.mattermark.com/companies/13601156","company_name":"Csoft Corp","domain":"csoftcorp.net","id":"13602832","url":"https://api.mattermark.com/companies/13602832","company_name":"Gareth, Inc.","domain":"garethinc.com","id":"13604890","url":"https://api.mattermark.com/companies/13604890","company_name":"Xpaseo","domain":"xpaseo.com","id":"13610146","url":"https://api.mattermark.com/companies/13610146","company_name":"Imagine IT","domain":"imagineit.com","id":"13610923","url":"https://api.mattermark.com/companies/13610923","company_name":"HTS Solutions Pvt Ltd","domain":"htssolutions.org","id":"13619836","url":"https://api.mattermark.com/companies/13619836","company_name":"Tgm Software","domain":"tgmsoftware.com","id":"13622956","url":"https://api.mattermark.com/companies/13622956","company_name":"Inaspan LLC","domain":"inaspan.com","id":"13627130","url":"https://api.mattermark.com/companies/13627130","company_name":"Forerunner Systems Inc","domain":"forerunnersystems.com","id":"13628312","url":"https://api.mattermark.com/companies/13628312","company_name":"Advanced Integrated Solutions, Inc.","domain":"aisconsulting.net","id":"13629029","url":"https://api.mattermark.com/companies/13629029","company_name":"Pounce Consulting","domain":"pouncecorp.com","id":"13629537","url":"https://api.mattermark.com/companies/13629537","company_name":"CloudServe Corporation","domain":"cloudservecorp.com","id":"13635102","url":"https://api.mattermark.com/companies/13635102","company_name":"Leivio Technologies","domain":"leivio.com","id":"13636749","url":"https://api.mattermark.com/companies/13636749","company_name":"Alpen Technology Group","domain":"alpentg.com","id":"13636754","url":"https://api.mattermark.com/companies/13636754","company_name":"National Schedule Masters","domain":"tractime.com","id":"13645065","url":"https://api.mattermark.com/companies/13645065","company_name":"RISA Technologies","domain":"risa.com","id":"13646467","url":"https://api.mattermark.com/companies/13646467","company_name":"Enterprise Answers, LLC","domain":"enterpriseanswers.com","id":"13647801","url":"https://api.mattermark.com/companies/13647801","company_name":"Office Automation Centers Inc","domain":"officeautomationcenter.com","id":"13650810","url":"https://api.mattermark.com/companies/13650810","company_name":"Mozgomedia","domain":"mozgomedia.com","id":"13652763","url":"https://api.mattermark.com/companies/13652763","company_name":"2000 Networking","domain":"network2000-hi.com","id":"13654103","url":"https://api.mattermark.com/companies/13654103","company_name":"Vega Imaging","domain":"vega-imaging.com","id":"13654874","url":"https://api.mattermark.com/companies/13654874","company_name":"Astha Inc.","domain":"asthainc.com","id":"13656103","url":"https://api.mattermark.com/companies/13656103","company_name":"Management Applied Programming","domain":"mapinc.com","id":"13657848","url":"https://api.mattermark.com/companies/13657848","company_name":"4Hilton Inc.","domain":"4hilton.com","id":"13658020","url":"https://api.mattermark.com/companies/13658020","company_name":"FCC Group","domain":"fccgroup.com","id":"13658316","url":"https://api.mattermark.com/companies/13658316","company_name":"Wavelength Datacom, Inc.","domain":"wavdata.com","id":"13661074","url":"https://api.mattermark.com/companies/13661074","company_name":"Xintex Corporation","domain":"xintex.com","id":"13663085","url":"https://api.mattermark.com/companies/13663085","company_name":"DCL Media Services","domain":"onlinecopycorp.com","id":"13667881","url":"https://api.mattermark.com/companies/13667881","company_name":"LMSPros","domain":"lmspros.com","id":"13669354","url":"https://api.mattermark.com/companies/13669354","company_name":"Sujansky \u0026 Associates, LLC","domain":"sujansky.com","id":"13669681","url":"https://api.mattermark.com/companies/13669681","company_name":"Felosoft LLC","domain":"felosoft.com","id":"13669759","url":"https://api.mattermark.com/companies/13669759","company_name":"Collaborative Technologies Inc","domain":"collaborationtech.net","id":"13670474","url":"https://api.mattermark.com/companies/13670474","company_name":"Freight Stream Inc","domain":"freightstream.com","id":"13675681","url":"https://api.mattermark.com/companies/13675681","company_name":"eDimension Consulting","domain":"edimensionconsulting.com","id":"13676806","url":"https://api.mattermark.com/companies/13676806","company_name":"LTT Net Solutions","domain":"lttnetsolutions.com","id":"13678223","url":"https://api.mattermark.com/companies/13678223","company_name":"OCRTI Consulting Corp","domain":"ocrti.com","id":"13679946","url":"https://api.mattermark.com/companies/13679946","company_name":"Mac Networks","domain":"macnetworks.com","id":"13681009","url":"https://api.mattermark.com/companies/13681009","company_name":"NetMost Web Technologies","domain":"netmostwebdesign.com"],"total_companies":4870,"page":97,"per_page":50'

SELECT * 
FROM OPENJSON(@json)
WITH (   
       id     int '$.companies.id' ,  
       [url]  nvarchar(max) '$.companies.url',  
       company_name nvarchar(max) '$.companies.company_name',  
       domain nvarchar(max)'$.companies.domain'  
     )

【问题讨论】：

【参考方案1】：

如果您想将所有JSON 数据作为结果集，您需要额外的APPLY 运算符和第二个OPENJSON() 调用（用于嵌套JSON 数组），使用显式架构定义：

T-SQL：

SELECT 
   j.total_companies, j.page, j.per_page,
   a.*
FROM OPENJSON(@json)
WITH (   
   total_companies int '$.total_companies',
   page int '$.page',
   per_page int '$.per_page',
   companies nvarchar(max) '$.companies' AS JSON
) j
CROSS APPLY OPENJSON(j.companies) 
WITH (
   id nvarchar(10) '$.id',
   url nvarchar(max) '$.url',
   company_name nvarchar(100) '$.company_name',
   domain nvarchar(max) '$.domain'
) a

输出（仅 50 条记录中的前 10 条记录）：

total_companies page    per_page    id          url                                             company_name            domain
4870            97      50          13463591    https://api.mattermark.com/companies/13463591   Modula4                 modula4.com
4870            97      50          13531979    https://api.mattermark.com/companies/13531979   Rae Development Corp    raedevelopment.com
4870            97      50          13537660    https://api.mattermark.com/companies/13537660   jBASE                   jbase.com
4870            97      50          13537769    https://api.mattermark.com/companies/13537769   D2Effects LLC           bitefx.com
4870            97      50          13537784    https://api.mattermark.com/companies/13537784   eSyncTraining           esynctraining.com
4870            97      50          13541751    https://api.mattermark.com/companies/13541751   Business Computing      bcinc.net
4870            97      50          13553270    https://api.mattermark.com/companies/13553270   KNIGHTLING INC.         knightling.com
4870            97      50          13560476    https://api.mattermark.com/companies/13560476   Netcentric systems      netcentricsystems.com
4870            97      50          13560643    https://api.mattermark.com/companies/13560643   Fortium Solutions, LLC  fortiumsolutions.com
4870            97      50          13561893    https://api.mattermark.com/companies/13561893   PMAC SERVICES INC       pmacservices.com

【讨论】：

【参考方案2】：

Companies 在您的情况下是数组。必须选择数组元素编号才能查看数据：

SELECT * 
FROM OPENJSON(@json)
WITH (   
       id     INT '$.companies[0].id' ,  
       [url]  NVARCHAR(MAX) '$.companies[0].url',  
       company_name NVARCHAR(MAX) '$.companies[0].company_name',  
       domain NVARCHAR(MAX) '$.companies[0].domain'  
     )
;

【讨论】：

此查询仅返回第一个公司元素。我希望返回公司数组中的所有公司。【参考方案3】：

这很简单...

您的 JSON 包含两个对象，第一个是 meta，似乎是 1:1 相关内容。最好直接调用JSON_VALUE() 进行查询。

第二个，companies 是一个嵌套的 JSON 数组。试试这个（为简洁起见）

DECLARE @json NVARCHAR(MAX)
SET @json =  N'"meta":"total_record_count":4870,"total_pages":98,"current_page":97,"per_page":50,"companies":["id":"13463591","url":"https://api.mattermark.com/companies/13463591","company_name":"Modula4","domain":"modula4.com","id":"13531979","url":"https://api.mattermark.com/companies/13531979","company_name":"Rae Development Corp","domain":"raedevelopment.com","id":"13537660","url":"https://api.mattermark.com/companies/13537660","company_name":"jBASE","domain":"jbase.com"]'

-这会带回 meta 值

SELECT JSON_VALUE(@json,'$.meta.total_record_count') AS total_record_count
        ,JSON_VALUE(@json,'$.meta.total_pages') AS total_pages
        ,JSON_VALUE(@json,'$.meta.current_page') AS current_page
        ,JSON_VALUE(@json,'$.meta.per_page') AS per_page

--这会带回 companies 数组：

SELECT A.*
FROM OPENJSON(@json,'$.companies')
WITH (   
       id     int ,  
       [url]  nvarchar(max),  
       company_name nvarchar(max),  
       domain nvarchar(max)  
     ) A;

提示：如果需要，您可以将它们与 CROSS JOIN... 结合使用...

【讨论】：

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