英文:
How to retrieve array element from a specific position in CosmosDB document?
问题
假设我有一个具有以下结构的文档：
{"VehicleDetailId": 1,"VehicleDetail": [{"Id": 1,"Make": "BMW"},{"Id": 1,"Model": "ABDS"},{"Id": 1,"Trim": "5.6L/ASMD"},{"Id": 1,"Year": 2008}]}
现在我想从VehicleDetail数组中检索位于特定位置的数组元素，比如我想检索第二个元素，即：
{"Id": 1,"Model": "ABDS"}
或者第三个元素，
{"Id": 1,"Trim": "5.6L/ASMD"}
我应该如何编写查询来实现这个目标？
英文:
Suppose I have a document with the following structure,
{"VehicleDetailId": 1,"VehicleDetail": [{"Id": 1,"Make": "BMW"},{"Id": 1,"Model": "ABDS"},{"Id": 1,"Trim": "5.6L/ASMD"},{"Id": 1,"Year": 2008}]}
Now I want to retrieve an array element located at a specific position from VehicleDetail array like I want to retrieve the second element, i.e.,
{"Id": 1,"Model": "ABDS"}
or the third,
{"Id": 1,"Trim": "5.6L/ASMD"}
How should I write the query to achieve this?
答案1
得分: 1
使用内置的ARRAY_SLICE函数。这允许您选择数组的一部分。
传递数组、起始位置和要选择的元素数量。
SELECT ARRAY_SLICE(c.VehicleDetail, 1, 1) As SecondElementFROM c
输出：
{"SecondElement": [{"Id": 1,"Model": "ABDS"}]}
英文:
Use the built-in ARRAY_SLICE function. This allows you to select part of an array.
Pass the array, starting position, number of elements to select.
SELECT ARRAY_SLICE(c.VehicleDetail, 1, 1) As SecondElementFROM c
Output:
{"SecondElement": [{"Id": 1,"Model": "ABDS"}]}
答案2
得分: 0
根据其他人的建议，可以使用ARRAY_SLICE。如果您想要选择数组中的特定元素，我们可以结合使用ARRAY_SLICE和ARRAY函数。
SELECT ARRAY_SLICE((ARRAY(SELECT a.Id FROM a IN c.VehicleDetail)), 1, 1) as SecondElement FROM c
英文:
As suggested by others, ARRAY_SLICE can be used. If you want to select specific element in array, we can combine ARRAY_SLICE and ARRAY functions
SELECT ARRAY_SLICE((ARRAY(SELECT a.Id FROM a IN c.VehicleDetail)), 1, 1) as SecondElement FROM c
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论