mongodb条件操作符
这节来说说mongodb条件操作符，"$lt", "$lte", "$gt", "$gte", "$ne"就是全部的比较操作符，对应于"<", "<=", ">", ">=","!="。
原子操作符："$and“, "$or“, "$nor“。
or查询有两种方式：一种是用$in来查询一个键的多个值，另一种是用$or来完成多个键值的任意给定值。$in相当于SQL语句的in操作。
$nin不属于。
$not与正则表达式联合使用时候极其有用，用来查询哪些与特定模式不匹配的文档。
$slice相当于数组函数的切片，检索一个数组文档并获取数组的一部分。限制集合中大量元素节省带宽。理论上可以通过 limit() 和 skip() 函数来实现，但是，对于数组就无能为力了。 $slice可以指定两个参数。第一个参数表示要返回的元素总数。第二个参数是可选的。如果使用的话，第一个参数定义的是偏移量，而第二个参数是限定的个数。第二个参数还可以指定一个负数。
$mod取摸操作。
$size操作符允许对结果进行筛选，匹配指定的元素数的数组。
$exists操作符允许返回一个特定的对象。注意：当前版本$exists是无法使用索引的，因此，使用它需要全表扫描。
$type操作符允许基于BSON类型来匹配结果。
1. 插入一些数据
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> use ttlsa_com switched to db ttlsa_com > db.mediaCollection.insert({ "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : ["Keanu Reeves","Carry-Anne Moss","Laurence Fishburne","Hugo Weaving","Gloria Foster","Joe Pantoliano"] }) > db.mediaCollection.insert({ "Type" : "DVD", Title : "Blade Runner", Released : 1982 }) > db.mediaCollection.insert({ "Type" : "DVD", Title : "Toy Story 3", Released : 2010 }) |
2. $gt (greater than)
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> db.mediaCollection.find({ Released : {$gt : 2000} }, { "Cast" : 0 }).toArray() [ { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ] |
3. $gte(greater than or equal to)
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> db.mediaCollection.find( { Released : {$gte : 1999 } }, { "Cast" : 0 } ).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999 }, { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ] |
4. $lt (less than)
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> db.mediaCollection.find( { Released : {$lt : 1999 } }, { "Cast" : 0 } ).toArray() [ { "_id" : ObjectId("5354823fd85b463e729a2e58"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 } ] |
5. $lte (less than or equal to)
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> db.mediaCollection.find( {Released : {$lte: 1999}}, { "Cast" : 0 } ).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999 }, { "_id" : ObjectId("5354823fd85b463e729a2e58"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 } ] |
6. 组合使用
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> db.mediaCollection.find( {Released : {$gte: 1990, $lt : 2010}}, { "Cast" : 0 } ).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999 } ] |
7. $ne (not equals)
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> db.mediaCollection.find( { Type : "DVD"} ).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Keanu Reeves", "Carry-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster", "Joe Pantoliano" ] }, { "_id" : ObjectId("5354823fd85b463e729a2e58"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 }, { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ] > db.mediaCollection.find( { Type : "DVD", Released : { $ne: 1999}} ).toArray() [ { "_id" : ObjectId("5354823fd85b463e729a2e58"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 }, { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ] |
8. $in/$or
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> db.mediaCollection.find( {Released : {$in : [1999,2008,2009] } }, { "Cast" : 0 } ).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999 } ] |
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> db.mediaCollection.find( {$or : [ {Released:1999}, {Released:2008}, {Released:2009} ] } ).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Keanu Reeves", "Carry-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster", "Joe Pantoliano" ] } ] |
9. $nin
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> db.mediaCollection.find( {Type : "DVD" }, { "Cast" : 0 }).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999 }, { "_id" : ObjectId("5354823fd85b463e729a2e58"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 }, { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ] > db.mediaCollection.find( {Released : {$nin : [1999,2008,2009] },Type : "DVD" }, { "Cast" : 0 }).toArray() [ { "_id" : ObjectId("5354823fd85b463e729a2e58"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 }, { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ] |
10. $all
与$in有点相似，只不过$all是所有属性要与文档匹配。$in只匹配其一就行。
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> db.mediaCollection.find( { Released : {$all : ["2010","2009"] } }, { "Cast" : 0 } ).toArray() [ ] |
11. 多个表达式
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> db.mediaCollection.find({ $or : [ { "Title" : "Toy Story 3" }, { "ISBN" : "987-1-4302-3051-9" } ] } ).toArray() [ { "_id" : ObjectId("5353462f93efef02c962da71"), "Type" : "Book", "Title" : "Definitive Guide to MongoDB, the", "ISBN" : "987-1-4302-3051-9", "Publisher" : "Apress", "Author" : [ "Membrey, Peter", "Plugge, Eelco", "Hawkins, Tim" ] }, { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ] |
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> db.mediaCollection.find({ "Type" : "DVD", $or : [ { "Title" : "Toy Story 3" }, { "ISBN" : "987-1-4302-3051-9" } ] }).toArray() [ { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ] |
11. 切片
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> db.mediaCollection.find({"Title" : "Matrix, The"}).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Keanu Reeves", "Carry-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster", "Joe Pantoliano" ] } ] > db.mediaCollection.find({"Title" : "Matrix, The"}, {"Cast" : {$slice: 3}}).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Keanu Reeves", "Carry-Anne Moss", "Laurence Fishburne" ] } ] > db.mediaCollection.find({"Title" : "Matrix, The"}, {"Cast" : {$slice: -3}}).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Hugo Weaving", "Gloria Foster", "Joe Pantoliano" ] } ] > db.mediaCollection.find({"Title" : "Matrix, The"}, {"Cast" : {$slice: [2,3] }}).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Laurence Fishburne", "Hugo Weaving", "Gloria Foster" ] } ] > db.mediaCollection.find({"Title" : "Matrix, The"}, {"Cast" : {$slice: [-5,4] }}).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Carry-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster" ] } ] |
12. $mod
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> db.mediaCollection.find( { Type : "DVD", Released : { $mod: [2,0] } } ).toArray() [ { "_id" : ObjectId("5354823fd85b463e729a2e58"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 }, { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ]
> db.mediaCollection.find( { Type : "DVD", Released : { $mod: [2,1] } } ).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Keanu Reeves", "Carry-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster", "Joe Pantoliano" ] } ] |
13. $size
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> db.mediaCollection.find( { Tracklist : {$size : 2} } ).toArray() [ { "_id" : ObjectId("5353463193efef02c962da73"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind", "Tracklist" : [ { "Track" : "1", "Title" : "Smells like teen spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] } ] > db.mediaCollection.find( { Cast : {$size : 1} } ).toArray() [ ] > db.mediaCollection.find( { Cast : {$size : 6} } ).toArray() [ { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Keanu Reeves", "Carry-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster", "Joe Pantoliano" ] } ] |
14. $exists
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> db.mediaCollection.find( { Author : {$exists : true } } ).toArray() [ { "_id" : ObjectId("5353462f93efef02c962da71"), "Type" : "Book", "Title" : "Definitive Guide to MongoDB, the", "ISBN" : "987-1-4302-3051-9", "Publisher" : "Apress", "Author" : [ "Membrey, Peter", "Plugge, Eelco", "Hawkins, Tim" ] } ] > db.mediaCollection.find( { Author : {$exists : false } } ).toArray() [ { "_id" : ObjectId("5353462f93efef02c962da72"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind" }, { "_id" : ObjectId("5353463193efef02c962da73"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind", "Tracklist" : [ { "Track" : "1", "Title" : "Smells like teen spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] }, { "_id" : ObjectId("53548225d85b463e729a2e57"), "Type" : "DVD", "Title" : "Matrix, The", "Released" : 1999, "Cast" : [ "Keanu Reeves", "Carry-Anne Moss", "Laurence Fishburne", "Hugo Weaving", "Gloria Foster", "Joe Pantoliano" ] }, { "_id" : ObjectId("5354823fd85b463e729a2e58"), "Type" : "DVD", "Title" : "Blade Runner", "Released" : 1982 }, { "_id" : ObjectId("53548254d85b463e729a2e59"), "Type" : "DVD", "Title" : "Toy Story 3", "Released" : 2010 } ] |
15. $type
根据BSON类型来检索集合中匹配的结果。
MongoDB中可以使用的类型如下表所示：
| 类型描述 | 类型值 |
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| Double | 1 |
| String | 2 |
| Object | 3 |
| Array | 4 |
| Binary data | 5 |
| Object id | 7 |
| Boolean | 8 |
| Date | 9 |
| Null | 10 |
| Regular expression | 11 |
| JavaScript code | 13 |
| Symbol | 14 |
| JavaScript code with scope | 15 |
| 32-bit integer | 16 |
| Timestamp | 17 |
| 64-bit integer | 18 |
| Min key | 255 |
| Max key | 127 |
下面这个实例是查询嵌入对象。
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> db.mediaCollection.find ( { Tracklist: { $type : 3 } } ).toArray() [ { "_id" : ObjectId("5353463193efef02c962da73"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind", "Tracklist" : [ { "Track" : "1", "Title" : "Smells like teen spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] } ] |
