Retrieve Selected Columns from MongoDB Document

To retrieve only specific columns from the MongoDB documents there are some different logics compare to SQL,

Two different ways to get the specific columns

• Including only the columns we need ( Giving ColumnName : true ( or ) 1  )
• Excluding all other columns (Giving ColumnName : false  ( or ) 1 )

Initial Data

{ "Name" : "Venki","Department" : "CSE","Languages" :[ { "speak" : "english","Write" : "telugu", "Expert" : "malayalam" } ] }

{ "Name" : "Rahul","Department" : "EEE","Languages" :[ { "speak" : "Bengali","Write" : "telugu", "Expert" : "malayalam"  }  ]  }

{ "Name" : "Brajesh","Department" : "CSE","Languages" :[ { "speak" : "Gujarathi", "Write" : "telugu", "Expert" : "malayalam" } ] }

{ "Name" : "vikram", "Department" : "CSE", "Languages" : [ {  "speak" : "Tamil", "Write" : "telugu", "Expert" : "English"  } ] }

Example of retrieving all the Names from the StudentDetails collection

db.studentDetails.find({},{Name:true,_id:false})

output will be as

{ "Name" : "Venki"}

{ "Name" : "Rahul"}

{ "Name" : "Brajesh"}

{ "Name" : "vikram"}

Example to get only name and department from Mongo Documents

db.studentDetails.find({},{_id:false,Languages:false})

output will be as

{  "Name" : "Venki",   "Department" : "CSE" }

{  "Name" : "Rahul",   "Department" : "EEE"  }

{  "Name" : "Brajesh",  "Department" : "CSE" }

{  "Name" : "vikram",  "Department" : "CSE"  }

Example of retrieving the name and department of name ‘venki’

db.studentDetails.find({Name:'Venki'},{Languages:false,_id:false})

output will be as

{ "Name" : "Venki", "Department" : "CSE" }