MongoDB Query Documents: Logical Operators

Using the $and Operator

The $and operator requires all specified conditions to be true for a document to match.

It is useful when you want to filter documents that meet multiple criteria simultaneously.

• Syntax: { $and: [ { condition1 }, { condition2 }, ... ] }
• Each condition is a standard MongoDB query expression.

Using the $or Operator

The $or operator matches documents that satisfy at least one of the specified conditions.

It is helpful when you want to find documents that meet any of several criteria.

• Syntax: { $or: [ { condition1 }, { condition2 }, ... ] }

Using the $not Operator

The $not operator inverts the effect of a query expression.

It is used to exclude documents that match a certain condition.

• Syntax: { field: { $not: { <operator-expression> } } }
• Commonly used with comparison operators like $gt, $eq, etc.

Using the $nor Operator

The $nor operator matches documents that fail all the specified conditions.

It is the logical NOR operation, meaning none of the conditions can be true.

• Syntax: { $nor: [ { condition1 }, { condition2 }, ... ] }

Practical Examples

Let's see some practical MongoDB queries using logical operators.