14c9ce97c5b78a0dc"), "name" : "xiaoqiang", "age" : 20 }
{ "_id" : ObjectId("5c939dd44c9ce97c5b78a0dd"), "name" : "xiaoqiang", "age" : 30 }
{ "_id" : ObjectId("5c939dd74c9ce97c5b78a0de"), "name" : "xiaoqiang", "age" : 40 }
> db.test_table01.remove({name:"xiaoqiang"},{justOne:true}) # 删除一条name等于xiaoqiang的数据
WriteResult({ "nRemoved" : 1 })
> db.test_table01.find()
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c939dd14c9ce97c5b78a0dc"), "name" : "xiaoqiang", "age" : 20 }
{ "_id" : ObjectId("5c939dd44c9ce97c5b78a0dd"), "name" : "xiaoqiang", "age" : 30 }
{ "_id" : ObjectId("5c939dd74c9ce97c5b78a0de"), "name" : "xiaoqiang", "age" : 40 }
> db.test_table01.remove({name:"xiaoqiang"}) # 删除所有name等于xiaoqiang的数据,共删除了3条数据
WriteResult({ "nRemoved" : 3 })
> db.test_table01.find()
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
6.?较运算符查询
MongoDB数据库中的?较运算符有：
= 等于,默认是等于判断,没有运算符
$lt ?于
$lte ?于等于
$gt ?于
$gte ?于等于
$ne 不等于
例子:
> db.test_table01.insert({name:"乔峰",hometown:"丐帮",gender:"male",age:32}) # 向数据表中插入四条数据
WriteResult({ "nInserted" : 1 })
> db.test_table01.insert({name:"段誉",hometown:"云南大理",gender:"male",age:22})
WriteResult({ "nInserted" : 1 })
> db.test_table01.insert({name:"虚竹",hometown:"少林寺",gender:"male",age:28})
WriteResult({ "nInserted" : 1 })
> db.test_table01.insert({name:"王语嫣",hometown:"燕子坞",gender:"female",age:18})
WriteResult({ "nInserted" : 1 })
> db.test_table01.find()
{ "_id" : ObjectId("5c939adc4c9ce97c5b78a0db"), "name" : "xiaozhao", "age" : 20 }
{ "_id" : ObjectId("5c93a1d64c9ce97c5b78a0e3"), "name" : "乔峰", "hometown" : "丐帮", "gender" : "male", "age" : 32 }
{ "_id" : ObjectId("5c93a1e74c9ce97c5b78a0e4"), "name" : "段誉", "hometown" : "云南大理", "gender" : "male", "age" : 22 }
{ "_id" : ObjectId("5c93a1f14c9ce97c5b78a0e5"), "name" : "虚竹", "hometown" : "少林寺", "gender" : "male", "age" : 28 }
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王语嫣", "hometown" : "燕子坞", "gender" : "female", "age" : 18 }
> db.test_table01.find({age:{$lt:20}}) # 查找年龄小于20岁的所有数据
{ "_id" : ObjectId("5c93a1fd4c9ce97c5b78a0e6"), "name" : "王语