Shulou(Shulou.com)06/01 Report--

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": {$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}

>

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