Operators

Performing operations on documents in a query

An operator in MerlinDB is a

keyword or symbol used in queries to specify conditions or perform operations on documents.

$eq (Access): Compares values ​​in a query in the collection;

$gt (Access): Finds documents where the value of a field is greater than the specified value;

$gte (Access): Finds documents where the value of a field is greater than or equal to the specified value;

$in (Access): Checks whether the value of a field is present in the query;

$lt (Access): Finds documents where the value of a field is less than the specified value;

$lte (Access): Finds documents where the value of a field is less than or equal to the specified value;

$ne (Access): Finds documents where the value of a field is not equal to the specified value;

$nin (Access): Finds documents where the value of a field is not in a specified set of values;

$and (Access): Combines multiple conditions into a single logical query;

$not (Access): Performs logical negation in a query expression;

$nor (Access): Finds documents that do not match all specified conditions;

$or (Access): Finds documents that match at least one of the conditions;

$regex (Access): Finds documents that match the regular expression (RegExp);

$exists (Access): Checks whether a field exists or not in a document;

$type (Access): Selects documents where the value of a field is of a specific BSON type;

$mod (Access): Checks whether the value of a field divided by a divisor has a specific remainder;

$text (Access): Performs textual searches in specific text fields;

$where (Access): Executes JavaScript code to select documents;

$all (Access): Selects documents where an array field contains all the specified elements;

$size (Access): Selects documents where the array field has a specific number of elements;

$set (Access): Updates values ​​of a field in a document;

$inc (Access): Increments (or decrements) the value of a numeric field in a document;

$order (Access): Ensures that documents are inserted in order;