Common commands for getting started with mongodb database

Select switch database ：
use articledb

insert data ：
db.comment.insert({bson data })

Query all the data ：
db.comment.find();

Condition query data ：
db.comment.find({ Conditions })

Query the first record that meets the criteria ：
db.comment.findOne({ Conditions })

Query the first few records that meet the criteria ：
db.comment.find({ Conditions }).limit( Number of pieces )

Query qualified skipped records ：
db.comment.find({ Conditions }).skip( Number of pieces )

Modifying data ：
db.comment.update({ Conditions },{ Revised data })
db.comment.update({ Conditions },{$set:{ To modify the field of the part : data })

Modify the data and add a field value automatically ：
db.comment.update({ Conditions },{$inc:{ Self increasing field : Step value }})

Delete data ：
db.comment.remove({ Conditions })

Statistics query ：
db.comment.count({ Conditions })

Fuzzy query ：
db.comment.find({ Field name :/ Regular expressions /})

Conditional comparison operations ：
db.comment.find({ Field name :{$gt: value }})

Contains the query ：
db.comment.find({ Field name :{$in:[ value 1, value 2]}})
db.comment.find({ Field name :{$nin:[ value 1, value 2]}})

Conditional join query ：
db.comment.find({$and:[{ Conditions 1},{ Conditions 2}]})
db.comment.find({$or:[{ Conditions 1},{ Conditions 2}]})