Spring Data MongoDB聚合-按计算值匹配 [英] Spring Data MongoDB aggregation - match by calculated value
问题描述
我有一个带有2个Number字段的文档集合，我需要根据计算出的条件过滤所有文档:
Number1/Number2 >= CONST%
如何使用Spring Data Mongo和Aggregation使其成为可能?
-更新-
我尝试了以下代码:
return new RedactAggregationOperation(
new BasicDBObject(
"$redact",
new BasicDBObject(
"$cond", new BasicDBObject()
.append("if", new BasicDBObject(
"$gte", Arrays.asList(new BasicDBObject(
"$divide",
Arrays.asList(
"$Number1",
new BasicDBObject(
"$cond",
new BasicDBObject()
.append("$or", Arrays.asList(
new BasicDBObject(
"$eq", new BasicDBObject(
"$Number2", 0)),
new BasicDBObject(
"$eq", new BasicDBObject(
new BasicDBObject(
"$ifNull",
new BasicDBObject(
"$Number2", 0)).toString(), 0))))
.append("then", 1000000)
.append("else", "$Number2")), CONSTANT_VAR))
)))
.append("then", "$$KEEP")
.append("else", "$$PRUNE")
)
)
);
但是出现错误"$ cond无法识别的参数:$ or" 您能协助解决这个问题吗?
您需要的是 $$PRUNE 在条件为假的情况下删除"文档.
此操作类似于使用
因为没有尚不支持 然后可以在
-更新- 对注释进行后续操作，以检查分区中 等效的Spring数据聚合(未试用) I've got a collection of documents with 2 Number fields and I need to filter all the documents based on a calculated condition: How can I make this posible using Spring Data Mongo and Aggregation? I've tried the following code: But there is an error "Unrecognized parameter to $cond: $or"
Could you please assist with this issue? What you need is the This operation is similar to having a Consider the following example which demonstrate the above concept:
Since there's no support for the which you can then use in
--UPDATE-- Follow-up from the comments, to check for nulls or zero values on the The following example assumes you have a placeholder value of 1 if either Equivalent Spring Data Aggregation (untested)
这篇关于Spring Data MongoDB聚合-按计算值匹配的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！$project 管道，该管道选择集合中的字段并创建一个新字段，该字段保存逻辑条件查询以及随后的
$redact 运算符(在撰写本文时)，一种解决方法是实现AggregationOperation接口，该接口使用一个要包含DBObject的类包装聚合操作:public class RedactAggregationOperation implements AggregationOperation {
private DBObject operation;
public RedactAggregationOperation (DBObject operation) {
this.operation = operation;
}
@Override
public DBObject toDBObject(AggregationOperationContext context) {
return context.getMappedObject(operation);
}
}
TypeAggregation中使用:Aggregation agg = newAggregation(
new RedactAggregationOperation(
new BasicDBObject(
"$redact",
new BasicDBObject(
"$cond", new BasicDBObject()
.append("if", new BasicDBObject(
"$gte", Arrays.asList(
new BasicDBObject(
"$divide", Arrays.asList( "$Number1", "$Number2" )
),
CONSTANT_VAR
)
)
)
.append("then", "$$KEEP")
.append("else", "$$PRUNE")
)
)
)
);
AggregationResults<Example> results = mongoTemplate.aggregate(
(TypedAggregation<Example>) agg, Example.class);
Number2字段中的空值或零值，您必须嵌套 Aggregation agg = newAggregation(
new RedactAggregationOperation(
new BasicDBObject(
"$redact",
new BasicDBObject(
"$cond", Arrays.asList(
new BasicDBObject(
"$gte", Arrays.asList(
new BasicDBObject(
"$divide", Arrays.asList(
"$Number1",
new BasicDBObject(
"$cond", Arrays.asList(
new BasicDBObject( "$or": Arrays.asList(
new BasicDBObject("$eq", Arrays.asList("$Number2", 0)),
new BasicDBObject("$eq", Arrays.asList(
new BasicDBObject("$ifNull", Arrays.asList("$Number2", 0)), 0
)
)
)
),
1, // placeholder value if Number2 is 0
"$Number2"
)
)
)
),
CONSTANT_VAR
)
), "$$KEEP", "$$PRUNE"
)
)
)
)
);
Number1/Number2 >= CONST%
--UPDATE--
return new RedactAggregationOperation(
new BasicDBObject(
"$redact",
new BasicDBObject(
"$cond", new BasicDBObject()
.append("if", new BasicDBObject(
"$gte", Arrays.asList(new BasicDBObject(
"$divide",
Arrays.asList(
"$Number1",
new BasicDBObject(
"$cond",
new BasicDBObject()
.append("$or", Arrays.asList(
new BasicDBObject(
"$eq", new BasicDBObject(
"$Number2", 0)),
new BasicDBObject(
"$eq", new BasicDBObject(
new BasicDBObject(
"$ifNull",
new BasicDBObject(
"$Number2", 0)).toString(), 0))))
.append("then", 1000000)
.append("else", "$Number2")), CONSTANT_VAR))
)))
.append("then", "$$KEEP")
.append("else", "$$PRUNE")
)
)
);
$redact operator in the aggregation framework which allows you to proccess the above logical condition with the $cond operator and uses the special operations $$KEEP to "keep" the document where the logical condition is true or $$PRUNE to "remove" the document where the condition was false.$project pipeline that selects the fields in the collection and creates a new field that holds the result from the logical condition query and then a subsequent $match, except that $redact uses a single pipeline stage which is more efficient.db.collection.aggregate([
{
"$redact": {
"$cond": [
{
"$gte": [
{ "$divide": ["$Number1", "$Number2"] },
CONSTANT_VAR
]
},
"$$KEEP",
"$$PRUNE"
]
}
}
])
$redact operator yet (at the time of writing), a workaround will be to implement an AggregationOperation interface that wraps the aggregation operation with a class to take in a DBObject:public class RedactAggregationOperation implements AggregationOperation {
private DBObject operation;
public RedactAggregationOperation (DBObject operation) {
this.operation = operation;
}
@Override
public DBObject toDBObject(AggregationOperationContext context) {
return context.getMappedObject(operation);
}
}
TypeAggregation:Aggregation agg = newAggregation(
new RedactAggregationOperation(
new BasicDBObject(
"$redact",
new BasicDBObject(
"$cond", new BasicDBObject()
.append("if", new BasicDBObject(
"$gte", Arrays.asList(
new BasicDBObject(
"$divide", Arrays.asList( "$Number1", "$Number2" )
),
CONSTANT_VAR
)
)
)
.append("then", "$$KEEP")
.append("else", "$$PRUNE")
)
)
)
);
AggregationResults<Example> results = mongoTemplate.aggregate(
(TypedAggregation<Example>) agg, Example.class);
Number2 field in the division, you would have to nest a $cond expression with the logic instead.Number2 does not exist/is null or have a value of zero:db.collection.aggregate([
{
"$redact": {
"$cond": [
{
"$gte": [
{
"$divide": [
"$Number1", {
"$cond": [
{
"$or": [
{ "$eq": ["$Number2", 0] },
{
"$eq": [
{ "$ifNull": ["$Number2", 0] }, 0
]
}
]
},
1, // placeholder value if Number2 is 0
"$Number2"
]
}
]
},
CONSTANT_VAR
]
},
"$$KEEP",
"$$PRUNE"
]
}
}
])
Aggregation agg = newAggregation(
new RedactAggregationOperation(
new BasicDBObject(
"$redact",
new BasicDBObject(
"$cond", Arrays.asList(
new BasicDBObject(
"$gte", Arrays.asList(
new BasicDBObject(
"$divide", Arrays.asList(
"$Number1",
new BasicDBObject(
"$cond", Arrays.asList(
new BasicDBObject( "$or": Arrays.asList(
new BasicDBObject("$eq", Arrays.asList("$Number2", 0)),
new BasicDBObject("$eq", Arrays.asList(
new BasicDBObject("$ifNull", Arrays.asList("$Number2", 0)), 0
)
)
)
),
1, // placeholder value if Number2 is 0
"$Number2"
)
)
)
),
CONSTANT_VAR
)
), "$$KEEP", "$$PRUNE"
)
)
)
)
);
