从openjson SQL Server 2016中的嵌套数组中删除对象 [英] Delete an object from nested array in openjson SQL Server 2016

问题描述

我想从 SQL Server 2016 中的以下 json 中删除 "AttributeName" : "Manufacturer":

I want to delete the "AttributeName" : "Manufacturer" from the below json in SQL Server 2016:

declare @json nvarchar(max) = '[{"Type":"G","GroupBy":[],
"Attributes":[{"AttributeName":"Class Designation / Compressive Strength"},{"AttributeName":"Size"},{"AttributeName":"Manufacturer"}]}]'

这是我试过但不起作用的查询

This is the query I tried which is not working

select JSON_MODIFY((
select JSON_Query(@json, '$[0].Attributes') as res),'$.AttributeName.Manufacturer', null) 

推荐答案

这是使用 for json 和 打开json.重点是:

Here is the working solution using the for json and open json. The point is to:

1. 确定您要删除的项目并将其替换为NULL.这是由 JSON_MODIFY(@json,'$[0].Attributes[2]', null) 完成的.我们只是说，取 Attributes 中的第二个元素并将其替换为 null

1. Identify the item you wish to delete and replace it with NULL. This is done by JSON_MODIFY(@json,'$[0].Attributes[2]', null). We're simply saying, take the 2nd element in Attributes and replace it by null

将此数组转换为行集.我们需要以某种方式摆脱这个 null 元素，这是我们可以在 SQL 中通过 where [value] is not null

Convert this array to a row set. We need to somehow get rid of this null element and that's something we can filter easily in SQL by where [value] is not null

将其全部组装回原始 JSON.这是由 FOR JSON AUTO

Assemble it all back to original JSON. That's done by FOR JSON AUTO

请记住此类 JSON 数据转换的一个重要方面:

JSON 设计用于信息交换或最终存储信息.但是您应该避免在 SQL 级别上进行更复杂的数据操作.

JSON is designed for information exchange or eventually to store the information. But you should avoid more complicated data manipulation on SQL level.

无论如何，这里的解决方案:

Anyway, solution here:

declare @json nvarchar(max) = '[{"Type": "G","GroupBy": [],"Attributes": [{"AttributeName": "Class Designation / Compressive Strength"}, {"AttributeName": "Size"}, {"AttributeName": "Manufacturer"}]}]';            

with src as
(
    SELECT * FROM OPENJSON(
        JSON_Query(
            JSON_MODIFY(@json,'$[0].Attributes[2]', null) , '$[0].Attributes'))
)
select JSON_MODIFY(@json,'$[0].Attributes', (
    select JSON_VALUE([value], '$.AttributeName') as [AttributeName] from src
    where [value] is not null
    FOR JSON AUTO 
)) 

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