In MySQL operators are used to further facilitate work with statements and clauses, and help they filter the retrieved values better.

Here is the list of MySQL operators:

MySQL operators
OPERATOR DESCRIPTION
ALL Allows comparisons with all the values given in a condition
AND Produces a result of a query if two or more of given conditions are met
ANY Allows comparisons with any of the values given in a condition
AS Used to specify an alternate or an alias name for a column or a table
ASC Used to order data by an ascending direction
BETWEEN Specifies a range of data to test the retrieved values against. Frequently used with the WHERE clause
ENABLE Enables (re-enables) an event
EXISTS Used for quick verification of data existence (tables and databases as well). Faster than ALL and ANY.
DESC Used to order data by a descending direction
DETERMINISTIC Used for testing inputs in stored procedures
DISTINCT Used to retrieve only "distinct" records from the database
IDENTIFIED BY Used in combination with CREATE USER (or similar) for the user identification
IN Determines if a specified value matches any values returned by the query
IN | OUT | INOUT Used in stored procedures to verify or retrieve parameters from a procedure
IS NOT NULL Verifies if the returned value is not null. Useful for data validity check
IS NULL Verifies if the returned value is null. Useful for data validity check
LIKE Very popular operator used in simple and complex search forms. It compares the query with a string or some other form of condition and retrieves the value
NOT Used in queries looking for negation of the given condition. Often used with the operator LIKE
NOT DETERMINISTIC Indicates that the result of a called procedure is not produced for that particular input
NOT EXISTS Used for a quick negative verification of data existence (tables and databases as well). Faster than ALL and ANY.
OR Produces a result of a query if any of given conditions is met
SOME Alias to ANY. See the manual for SOME
UNION Combines (joins) two queries that have equal number of columns and data types
UNION ALL Compares the validity of two table's data and combines (joins) them between two databases