SQL Functions

These functions can be used in your SQL statements.

Logical Functions

IF(expr1,expr2,expr3)	If expr1 is not zero and not null, return expr2. Otherwise, return expr3.
IFNULL(expr1,expr2)	If expr1 is not NULL, return expr1; Otherwise, return expr2.

String Functions

CONCAT(str1,str2,...)	Concatenates the strings. Returns the result.
LENGTH(str)	Returns the length of the string, in bytes. (A mult-byte character counts as multiple bytes.)

Date Functions

DATE_ADD
DATEDIFF
CURDATE
NOW
CURTIME
DATE_FORMAT
DATE_SUB
DATE
DAYOFMONTH
DAYNAME
DAYOFWEEK
DAYOFYEAR
EXTRACT
FROM_UNIXTIME
HOUR
LAST_DAY
MINUTE
MONTH
MONTHNAME
SEC_TO_TIME
SECOND
STR_TO_DATE
SUBTIME
TIME_TO_SEC
TIME
TIMEDIFF
TO_DAYS
UNIX_TIMESTAMP
YEAR

Aggregate Functions

SUM(expr) SUM(DISTINCT expr)	Returns the sum of the values in the expression, or of the distinct values in the expression. Returns NULL if the expression has no values.
AVG(expr) AVG(DISTINCT expr)	Returns the average of the values in the expression, or of the distinct values in the expression. Returns NULL if the expression has no values.
COUNT(expr)	Returns a count of the number of non-NULL values of expr in the rows retrieved by a SELECT statement Returns 0 if there were no matching rows.
COUNT(*)	Returns a count of rows, whether or not they contain NULL values.
COUNT(DISTINCT expr   [, expr ...])	Returns a count of rows with different non-NULL expr values.
MAX
MIN
STD
VARIANCE
ROUND