Built-In Function and Operator Reference 2098 Name Description Introduced Deprecated CONNECTION_ID() Return the connection ID (thread ID) for the connection CONV() Convert numbers between different number bases CONVERT() Cast a value as a certain type CONVERT_TZ() Convert from one time zone to another COS() Return the cosine COT() Return the cotangent COUNT() Return a count of the number of rows returned COUNT(DISTINCT) Return the count of a number of different values CRC32() Compute a cyclic redundancy check value CUME_DIST() Cumulative distribution value CURDATE() Return the current date CURRENT_DATE() , CURRENT_DATE Synonyms for CURDATE() CURRENT_ROLE() Return the current active roles CURRENT_TIME() , CURRENT_TIME Synonyms for CURTIME() CURRENT_TIMESTAMP() , CURRENT_TIMESTAMP Synonyms for NOW() CURRENT_USER() , CURRENT_USER The authenticated user name and host name CURTIME() Return the current time DATABASE() Return the default (current) database name DATE() Extract the date part of a date or datetime expression DATE_ADD() Add time values (intervals) to a date value DATE_FORMAT() Format date as specified DATE_SUB() Subtract a time value (interval) from a date DATEDIFF() Subtract two dates