Checking if a field contains a string
https://docs.mongodb.com/manual/reference/sql-comparison/
http://php.net/manual/en/mongo.sqltomongo.php
MySQL
SELECT * FROM users WHERE username LIKE "%Son%"
MongoDB
db.users.find({username:/Son/})
As Mongo shell support regex, that's completely possible.
db.users.findOne({"username" : /.*son.*/});
If we want the query to be case-insensitive, we can use "i" option, like shown below:
db.users.findOne({"username" : /.*son.*/i});
See: http://www.mongodb.org/display/DOCS/Advanced+Queries#AdvancedQueries-RegularExpressions
You can do it with the following code.
db.users.findOne({"username" : {$regex : "son"}});