Query and Projection Operators of MongoDB


Query operators provide ways to locate data within the database and projection operators modify how data is presented.

  • Query Selectors


Comparison Operators
For comparison of different BSON type values

in MongoDB in SQL Description
$eq = Matches values that are equal to a specified value.
$gt > Matches values that are greater than a specified value.
$gte >= Matches values that are greater than or equal to a specified value.
$lt < Matches values that are less than a specified value.
$lte <= Matches values that are less than or equal to a specified value.
$ne != Matches all values that are not equal to a specified value.
$in in(x,y..) Matches any of the values specified in an array.
$nin not in(x,y,…) Matches none of the values specified in an array.

Logical Operators

in MongoDB in SQL Description
$or or Joins query clauses with a logical OR returns all documents that match the conditions of either clause.
$and and Joins query clauses with a logical AND returns all documents that match the conditions of both clauses.
$not not Inverts the effect of a query expression and returns documents that do not match the query expression.
$nor Joins query clauses with a logical NOR returns all documents that fail to match both clauses.

Element Operators

Name Description
$exists Matches documents that have the specified field.
$type Selects documents if a field is of the specified type.