MongoDB 条件查询--比较操作

$type操作符

db.user.find({name:{$type:2}}); //查找name数据类型为string的

$gt – greater than >

# 查找年龄大于50的
db.user.find({age:{'$gt':50}});

/* 1 */
{
    "_id" : ObjectId("5b604ac423cc834a5495d780"),
    "name" : "lhc",
    "age" : 78.0
}

/* 2 */
{
    "_id" : ObjectId("5b6068d64b008f4e969ef4ff"),
    "name" : "bbbb",
    "age" : 88.0
}

$gte – gt equal >=

db.user.find({age:{'$gte':88}}); //查找age大于等于88的

/* 1 */
{
    "_id" : ObjectId("5b6068d64b008f4e969ef4ff"),
    "name" : "bbbb",
    "age" : 88.0
}

$lt – less than <

db.user.find({age:{'$lt':50}}); //age小于50的

/* 1 */
{
    "_id" : ObjectId("5b6068c94b008f4e969ef4fd"),
    "name" : "jay",
    "age" : 20.0
}

/* 2 */
{
    "_id" : ObjectId("5b6068cf4b008f4e969ef4fe"),
    "name" : "aaa",
    "age" : 10.0
}

/* 3 */
{
    "_id" : ObjectId("5b6068de4b008f4e969ef500"),
    "name" : "weeee",
    "age" : 0.0
}

/* 4 */
{
    "_id" : ObjectId("5b6068e54b008f4e969ef501"),
    "name" : "weeee",
    "age" : 30.0
}

lte – lt equal <=

db.user.find({age:{'$lte':20}}); //age小于等于20

/* 1 */
{
    "_id" : ObjectId("5b6068c94b008f4e969ef4fd"),
    "name" : "jay",
    "age" : 20.0
}

/* 2 */
{
    "_id" : ObjectId("5b6068cf4b008f4e969ef4fe"),
    "name" : "aaa",
    "age" : 10.0
}

/* 3 */
{
    "_id" : ObjectId("5b6068de4b008f4e969ef500"),
    "name" : "weeee",
    "age" : 0.0
}

$ne – not equal !=

```
db.user.find({age:{'$ne':10}}); //age != 10

/* 1 */
{
    "_id" : ObjectId("5b604ac423cc834a5495d780"),
    "name" : "lhc",
    "age" : 78.0
}

/* 2 */
{
    "_id" : ObjectId("5b6068c94b008f4e969ef4fd"),
    "name" : "jay",
    "age" : 20.0
}

/* 3 */
{
    "_id" : ObjectId("5b6068d64b008f4e969ef4ff"),
    "name" : "bbbb",
    "age" : 88.0
}

/* 4 */
{
    "_id" : ObjectId("5b6068de4b008f4e969ef500"),
    "name" : "weeee",
    "age" : 0.0
}

/* 5 */
{
    "_id" : ObjectId("5b6068e54b008f4e969ef501"),
    "name" : "weeee",
    "age" : 30.0
}

$eq – equal =

db.user.find({age:{'$eq':10}}); //age =10

/* 1 */
{
    "_id" : ObjectId("5b6068cf4b008f4e969ef4fe"),
    "name" : "aaa",
    "age" : 10.0
}

联合查询

db.user.find({age:{'$lte':70,'$gte':10}}); // age >=10 and age <=70

/* 1 */
{
    "_id" : ObjectId("5b6068c94b008f4e969ef4fd"),
    "name" : "jay",
    "age" : 20.0
}

/* 2 */
{
    "_id" : ObjectId("5b6068cf4b008f4e969ef4fe"),
    "name" : "aaa",
    "age" : 10.0
}

/* 3 */
{
    "_id" : ObjectId("5b6068e54b008f4e969ef501"),
    "name" : "weeee",
    "age" : 30.0
}