1 ) . 大于,小于,大于或等于,小于或等于 $gt:大于 $lt:小于 $gte:大于或等于 $lte:小于或等于 例子: db.collection.find({ "field" : { $gt: value } } ); // greater than : field > value db.collection.find({ "field" : { $lt: value } } ); // less than : field < value db.c...
我们可以通过totalIndexSize()函数来查看当前集合中索引的大小,单位为字节。 语法格式:db.COLLECTION_NAME.totalIndexSize(detail) 参数解释:detail可选参数,传入除0或false外的任意数据,会显示该集合中每个索引的大小及集合中索引的总大小。如果传入0或false则只显示该集合中所有索引的总大小。默认值为...
代码运行次数:0 运行 AI代码解释 // value1 < field < valuedb.collection.find({"field":{$gt:value1,$lt:value2}}); 2. value是否在List中:in 和 not in 代码语言:javascript 代码运行次数:0 运行 AI代码解释 db.collection.find({"field":{$in:array}}); ...
You cannot use $size to find a range of sizes (for example: arrays with more than 1 element). If you need to query for a range, create an extra size field that you increment when you add elements. 7)$exists $exists用来判断一个元素是否存在: 如: db.things.find( { a : { $exists ...
Bson 中,除了基本的 JSON 类型:string,integer,boolean,double,null,array 和 object,mongo 还使用了特殊的数据类型。这些类型包括 date,object id,binary data,regular expression 和 code。每一个驱动都以特定语言的方式实现了这些类型,查看你的驱动的文档来获取详 ...
创建集合:db.createCollection(name,options)db.createCollection('stu', { capped:true, size:200, max:2} )参数capped:默认值为false表示不设置上限,值为true表示设置上限参数size:集合所占用的字节数。 当capped值为true时,需要指定此参数,表示上限大小,当文档达到上限时, 会将之前的数据覆盖,单位为字节参数max...
: [ "Lily", "Jobs", "Lucy", "Zhang San" ] }// $sizedb.grade1.find({"friends" :{$size:4}})//{ "_id" : 1, "name" : "Tom1", "age" : 9, "friends" : [ "Lily", "Jobs", "Lucy", "Zhang San" ] }// $slicedb.collection.find( { field: value }, { array: {$sl...
You cannot use$sizeto find a range of sizes (for example: arrays with more than 1 element). If you need to query for a range, create an extrasizefield that you increment when you add elements. 7)$exists $exists用来判断一个元素是否存在: ...
To avoid any latency issues, you should ensure that the pool size is greater than the number of opened change streams. For details see the maxPoolSize setting. Sharded Cluster Considerations When a change stream is opened on a sharded cluster: The mongos creates individual change streams on ...
我试图找到数组字段的和,然后,想过滤大于100的和。 { name: 'John', grades: [60, 70, 40] # sum of this array = 170 (take this) }, { name: 'Doe', grades: [30, 20, 10] # sum of this array = 60 (don't take this)