Use of where condition in MongoDB
Example of using select(find) query with where condition in MongoDB.
Check the complete table detail as follows
db.employees.find( {},{_id:0})
{ "name" : "abc123", "age" : 55, "status" : "A" }
{ "name" : "qwe", "age" : 20, "status" : "A" }
{ "name" : "zxc", "age" : 25, "status" : "A" }
{ "name" : "asd", "age" : 35, "status" : "A" }
{ "name" : "kkk", "age" : 23, "status" : "N" }
Use of where clause with EQUAL operator in MongoDB
---In RDBMS example
select * from employees where status = 'A';
--In MongoDB
db.employees.find( {status: "A"} )
db.employees.find( {status:"A"},{_id:0})
Output:
{ "name" : "abc123", "age" : 55, "status" : "A" }
{ "name" : "qwe", "age" : 20, "status" : "A" }
{ "name" : "zxc", "age" : 25, "status" : "A" }
{ "name" : "asd", "age" : 35, "status" : "A" }
Use of IN-EQUAL operator in Where Clause
-- In RDBMS
select * from employees where status != 'A';
--In MongoDB
db.employees.find( { status: { $ne: "A" } } )
db.employees.find( { status: { $ne: "A" } }, {_id:0})
Output:
{ "name" : "kkk", "age" : 23, "status" : "N" }
Use of greater then operator in where clause
-- In RDBMS
SELECT * FROM employees WHERE age >= 25
--In MongoDB
db.employees.find( { status: "A",age:{$gte:25} } )
db.employees.find( { status: "A",age:{$gte:35} }, {_id:0})
OUTPUT:
{ "name" : "abc123", "age" : 55, "status" : "A" }
{ "name" : "asd", "age" : 35, "status" : "A" }
