Mongo Advanced query
1. Conditional operator
(1) conditional operator
Db.collection.find ({"field": {$gt: value}}); / / greater than: field > value
Db.collection.find ({"field": {$lt: value}}); / / less than: field
< value db.collection.find({ "field" : { $gte: value } } ); // 大于等于: field >= value
Db.collection.find ({"field": {$lte: value}}); / less than or equal to: field db.user.find ()
{"_ id": ObjectId ("4fb4af85afa87dc1bed94330"), "age": 7, "length_1": 30}
{"_ id": ObjectId ("4fb4af89afa87dc1bed94331"), "age": 8, "length_1": 30}
{"_ id": ObjectId ("4fb4af8cafa87dc1bed94332"), "age": 6, "length_1": 30}
> db.user.find ({age: {$mod: [6jue 1]}})
{"_ id": ObjectId ("4fb4af85afa87dc1bed94330"), "age": 7, "length_1": 30}
(5) $ne is not equal to
Query data where the value of age is not equal to 7
> db.user.find ({age: {$ne:6}})
{"_ id": ObjectId ("4fb4af85afa87dc1bed94330"), "age": 7, "length_1": 30}
{"_ id": ObjectId ("4fb4af89afa87dc1bed94331"), "age": 8, "length_1": 30}
> db.user.find ({age: {$ne:7}})
{"_ id": ObjectId ("4fb4af89afa87dc1bed94331"), "age": 8, "length_1": 30}
{"_ id": ObjectId ("4fb4af8cafa87dc1bed94332"), "age": 6, "length_1": 30}
(6) $in contains
Query data with a value of age in the range of 7 and 8
> db.user.find ({age: {$in: [7 in 8]}})
{"_ id": ObjectId ("4fb4af85afa87dc1bed94330"), "age": 7, "length_1": 30}
{"_ id": ObjectId ("4fb4af89afa87dc1bed94331"), "age": 8, "length_1": 30}
(7) min does not contain
Query data whose value of age is outside the range of 7 and 8
> db.user.find ({age: {$nin: [7 nin 8]}})
{"_ id": ObjectId ("4fb4af8cafa87dc1bed94332"), "age": 6, "length_1": 30}
(8) number of elements in the $size array
Match db.users.find ({favorite_number: {$size: 3}})
Mismatch db.users.find ({favorite_number: {$size: 2}})
> db.user.find ({favorite_number: {$size:3}})
{"_ id": ObjectId ("579eee3d8aeb5abda0d54b5e"), "name": "David", "age": 26, "favorite_number": [6, 7, 9]}
> db.user.find ({favorite_number: {$size:2}})
>
(9) regular expression matching
Query data for which name does not begin with T
Db.user.find ()
{"_ id": ObjectId ("4fb5faaf6d0f9d8ea3fc91a8"), "name": "Tony", "age": 20}
{"_ id": ObjectId ("4fb5fab96d0f9d8ea3fc91a9"), "name": "Joe", "age": 10}
> db.user.find ({name: {$not:/ ^ T. * /}})
{"_ id": ObjectId ("4fb5fab96d0f9d8ea3fc91a9"), "name": "Joe", "age": 10}
>
(10) Javascript query and $where query
Query data with a greater than 3. The following query methods go the same way.
Db.c1.find ({a: {$gt: 3}})
Db.c1.find ({$where: "this.a > 3"})
Db.c1.find ("this.a > 3")
F = function () {return this.a > 3;} db.c1.find (f)
(11) number of count query records
> db.user.find ()
{"_ id": ObjectId ("4fb5faaf6d0f9d8ea3fc91a8"), "name": "Tony", "age": 20}
{"_ id": ObjectId ("4fb5fab96d0f9d8ea3fc91a9"), "name": "Joe", "age": 10}
> db.user.find () .count ()
two
>
(12) skip limit returns the starting point of the record
Query item 2 data in user
> db.user.find ()
{"_ id": ObjectId ("4fb5faaf6d0f9d8ea3fc91a8"), "name": "Tony", "age": 20}
{"_ id": ObjectId ("4fb5fab96d0f9d8ea3fc91a9"), "name": "Joe", "age": 10}
> db.user.find () .skip (1) .limit (1)
{"_ id": ObjectId ("4fb5fab96d0f9d8ea3fc91a9"), "name": "Joe", "age": 10}
>
(13) sort sorting
Query C1 table is sorted in ascending order of age
> db.user.find () .sort ({age:-1})
{"_ id": ObjectId ("4fb5faaf6d0f9d8ea3fc91a8"), "name": "Tony", "age": 20}
{"_ id": ObjectId ("4fb5fab96d0f9d8ea3fc91a9"), "name": "Joe", "age": 10}
> db.user.find () .sort ({age:1})
{"_ id": ObjectId ("4fb5fab96d0f9d8ea3fc91a9"), "name": "Joe", "age": 10}
{"_ id": ObjectId ("4fb5faaf6d0f9d8ea3fc91a8"), "name": "Tony", "age": 20}
>
(14) Vernier
For (var iTunes 1) for (var c=db.user.find (); c.hasNext ();) {printjson (c.next ());}
{"_ id": ObjectId ("579ef6198aeb5abda0d54b5f"), "x": 1}
{"_ id": ObjectId ("579ef6198aeb5abda0d54b60"), "x": 2}
{"_ id": ObjectId ("579ef6198aeb5abda0d54b61"), "x": 3}
{"_ id": ObjectId ("579ef6198aeb5abda0d54b62"), "x": 4}
{"_ id": ObjectId ("579ef6198aeb5abda0d54b63"), "x": 5}
{"_ id": ObjectId ("579ef6198aeb5abda0d54b64"), "x": 6}
{"_ id": ObjectId ("579ef6198aeb5abda0d54b65"), "x": 7}
{"_ id": ObjectId ("579ef6198aeb5abda0d54b66"), "x": 8}
{"_ id": ObjectId ("579ef6198aeb5abda0d54b67"), "x": 9}
>
