MongoDB Simple Select Query Example

by Didin J., updated on Sep 03, 2019 MongoDB Simple Select Query Example

How to select query to get required data from collection, it's similar to select query in SQL to get specific data from table.

Today I will show you a simple select query similar to standard SQL. This might feel different for who used RDMS before. The SELECT clause in SQL similar to find() operators in MongoDB. WHERE clause in SQL similar to the first bracket "{}" of find() operator.

Basic Query

Take a look at the SQL example below:

SELECT * FROM CITY

This means all rows and fields in cities table will be returned in query results. Using MongoDB will be a little different, which the syntax will be like this:

db.city.find()

Same results will be showed and of course, they are the different format.

SQL result:

ID         |    CITI_NAME      |     PROV_NAME
===============================================
         1 | JAKARTA           | DKI JAKARTA   

MongoDB Result:

{ "_id" : ObjectId("584a13d5b65761be678d4dd4"), "citiName" : "Jakarta", "provName" : "DKI Jakarta" }

In SQL usually using INTEGER or LONG as ID with unique and incremental property and MongoDB basically using ObjectId as id.

And here's syntax comparisson:

SQL MongoDB Notes
SELECT * find() Select clause
FROM - From clause
CITY city Table/Collections Name
- db Initial mongodb syntax

Using Where Clause

Now we try to query the city table with where clause. The scenario is getting the table row which has provName "Jawa Barat".

SQL:

SELECT * FROM CITY WHERE PROV_NAME = 'JAWA BARAT'

MongoDB:

db.city.find({provName:"Jawa Barat"})

Look, MongoDB has simpler where query syntax which just adds fields to find params.

That it's for now.

That just the basic. If you need more deep learning about MongoDB or related you can take the following cheap course:

Thanks

Loading…