Spring Data Mongo-如何获取嵌套的嵌套数组以获取嵌套值? [英] Spring Data Mongo - How to get the nested distinct array for nested value?
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问题描述
I'm taking a reference from : Spring Data Mongo - Perform Distinct, but doesn't wants to pull embedded documents in results and asking another questions.
我想找到"subdeptCd":"1D"的技术列表.我们该怎么做?
I want to find technology list where "subdeptCd" : "1D". How can we do that ?
{
"firstName" : "Laxmi",
"lastName" : "Dekate",
.....
.......
.....
"departments" : {
"deptCd" : "Tax",
"deptName" : "Tax Handling Dept",
"status" : "A",
"subdepts" : [
{
"subdeptCd" : "1D",
"subdeptName" : "Tax Clearning",
"desc" : "",
"status" : "A"
"technology" : [
{
"technologyCd" : "4C",
"technologyName" : "Cloud Computing",
"desc" : "This is best certficate",
"status" : "A"
}
]
}
]
},
},
{
"firstName" : "Neha",
"lastName" : "Parate",
.....
.......
.....
"departments" : {
"deptCd" : "Tax Rebate",
"deptName" : "Tax Rebate Handling Dept",
"status" : "A",
"subdepts" : [
{
"subdeptCd" : "1D",
"subdeptName" : "Tax Clearning",
"desc" : "",
"status" : "A"
"technology" : [
{
"technologyCd" : "9C",
"technologyName" : "Spring Cloud",
"desc" : "This is best certficate post Google",
"status" : "A"
}
]
}
]
},
}
推荐答案
通过这种聚合,您可以获得独特的技术(technology
数组元素):
You can get distinct technologies (technology
array elements) with this aggregation:
db.depts.aggregate( [
{
$unwind: "$departments.subdepts"
},
{
$unwind: "$departments.subdepts.technology"
},
{
$match: { "departments.subdepts.subdeptCd": "1D" }
},
{
$group: { _id: "$departments.subdepts.technology.technologyCd", tech: { $first: "$departments.subdepts.technology" } }
},
{
$replaceRoot: { newRoot: "$tech" }
}
] )
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