MariaDB - Useful Functions

COUNT

It counts the number of records.

Example − SELECT COUNT(*) FROM customer_table;

MIN

It reveals the minimum value of a set of records.

Example − SELECT organization, MIN(account) FROM contracts GROUP BY organization;

MAX

It reveals the maximum value of a set of records.

Example − SELECT organization, MAX(account_size) FROM contracts GROUP BY organization;

AVG

It calculates the average value of a set of records.

Example − SELECT AVG(account_size) FROM contracts;

SUM

It calculates the sum of a set of records.

Example − SELECT SUM(account_size) FROM contracts;

CURDATE()

It returns the date in yyyy-mm-dd or yyyymmdd format.

Example − SELECT CURDATE();

DATE()

It returns the date in multiple formats.

Example −CREATE TABLE product_release_tbl (x DATE);

CURTIME()

It returns the time in HH:MM:SS or HHMMSS.uuuuuu format.

Example − SELECT CURTIME();

DATE_SUB()

It adds or subtracts a number of days from the specified date.

Example − SELECT DATE_SUB('2016-02-08', INTERVAL 60 DAY);

DATEDIFF()

It determines the days between two dates.

Example − SELECT DATEDIFF('2016-01-01 23:59:59','2016-01-03');

DATE ADD()

It adds or subtracts any unit of time to/from the date and time.

Example − SELECT DATE_ADD('2016-01-04 23:59:59', INTERVAL 22 SECOND);

EXTRACT()

It extracts a unit from the date.

Example − SELECT EXTRACT(YEAR FROM '2016-01-08');

NOW()

It returns the current date and time in either yyyy-mm-dd hh:mm:ss or yyyymmddhhmmss.uuuuuu format.

Example − SELECT NOW();

DATE FORMAT()

It formats the date in accordance with the specified format string.

Example − SELECT DATE_FORMAT('2016-01-09 20:20:00', '%W %M %Y');

HOUR()

It returns the hour of the time, or the hours elapsed.

Example − SELECT HOUR('19:17:09');

LOCALTIME()

It functions exactly like NOW().

MICROSECOND()

It returns the microseconds of the time.

Example − SELECT MICROSECOND('16:30:00.543876');

MINUTE()

It returns the minutes of the time.

Example − SELECT MINUTE('2016-05-22 17:22:01');

SECOND()

It returns the seconds of the date.

Example − SELECT SECOND('2016-03-12 16:30:04.000001');

TIME_FORMAT()

It formats the time in accordance with the specified format string.

Example − SELECT TIME_FORMAT('22:02:20', '%H %k %h %I %l');

TIMESTAMP()

It provides a timestamp for an activity in the format yyyy-mm-dd hh:mm:dd.

Example − CREATE TABLE orders_ (ID INT, tmst TIMESTAMP);

TRUNCATE()

It returns a truncated number to decimal place specification.

Example − SELECT TRUNCATE(101.222, 1);

COS()

It returns the cosine of x radians.

Example − SELECT COS(PI());

CEILING()

It returns the smallest integer not below x.

Example − SELECT CEILING(2.11);

DEGREES()

It converts radians to degrees.

Example − SELECT DEGREES(PI());

DIV()

It performs integer division.

Example − SELECT 100 DIV 4;

EXP()

It returns e to the power of x.

Example − SELECT EXP(2);

FLOOR()

It returns the largest integer not above x.

Example − SELECT FLOOR(2.01);

LN()

It returns the natural logarithm of x.

Example − SELECT LN(3);

LOG()

It returns the natural logarithm or the logarithm to a given base.

Example − SELECT LOG(3);

SQRT()

It returns the square root.

Example − SELECT SQRT(16);

INSTR()

It returns the position of the first instance of a substring.

Example − SELECT INSTR('rambutan', 'tan');

RIGHT()

It returns the rightmost string characters.

Example − SELECT RIGHT('rambutan', 3);

LENGTH()

It returns the byte length of a string.

Example − SELECT LENGTH('rambutan');

LOCATE()

It returns the position of the first instance of a substring.

Example − SELECT LOCATE('tan', 'rambutan');

INSERT()

It returns a string, with a specified substring at a certain position, that was modified.

Example − SELECT INSERT('ramputan', 4, 1, 'b');

LEFT()

It returns the leftmost characters.

Example − SELECT LEFT('rambutan', 3);

UPPER()

It changes characters to uppercase.

Example − SELECT UPPER(lastname);

LOWER()

It changes characters to lowercase.

Example − SELECT LOWER(lastname);

STRCMP()

It compares strings and returns 0 when they are equal.

Example − SELECT STRCMP('egg', 'cheese');

REPLACE()

It returns a string after replacing characters.

Example − SELECT REPLACE('sully', 'l', 'n');

REVERSE()

It reverses characters in a string.

Example − SELECT REVERSE('racecar');

REPEAT()

It returns a string repeating given characters x times.

Example − SELECT REPEAT('ha ', 10);

SUBSTRING()

It returns a substring from a string, starting at position x.

Example − SELECT SUBSTRING('rambutan',3);

TRIM()

It removes trailing/leading characters from a string.

Example − SELECT TRIM(LEADING '_' FROM '_rambutan');