MongoDB – How to query a MongoDB Collection (Part I)
LIKE OPERATOR – ‘NNN%’
// select all users where _id like '61fefc%'
db.users.find({"_id":/^61fefc/})
LIKE OPERATOR – ‘%NNN’
// select all users where name like '%er'
db.users.find({"name":/er$/})
LIKE OPERATOR – ‘%NNN%’
// select all users where name like '%ED%'
db.users.find({"company":/ED/})
AND WITH OR
// select all users where age <=34 and (isActive = false or gender='female')
db.users.find(
{
age: {$lte:34},
$or:
[
{isActive: false},
{gender: 'female'}
]
}
)
IN
// select all users where isActive = false and age in (33,34)
db.users.find(
{
isActive:false,
age: {$in: [33,34]}
}
)
GROUP BY
// select gender, Sum(age), AVG(age) from users where gender="male")
// group by gender having count>=1 order by gender
db.users.aggregate(
[
{$match:{ gender: "male"}},
{$group: { _id: "$gender", TotalAge: {$sum: "$age"},AvgAge: {$avg: "$age"}, CountRow: {$sum: 1}}},
{$match: {CountRow: {$gte: 1}}},
{$sort: {_id: 1}},
{$project: { _id: 1, TotalAge: 1, AvgAge: 1, CountRow:1 }}
]
)
