get random data from mysql

SELECT * FROM your_table_name
ORDER BY RAND()
LIMIT 5; //use limit to get limited infoSELECT * FROM table_name
ORDER BY RAND()
LIMIT 1;## MySQL function to generate random string of specified length
DROP function if exists get_string;
delimiter $$
CREATE FUNCTION get_string(in_strlen int) RETURNS VARCHAR(500) DETERMINISTIC
BEGIN 
set @var:='';
while(in_strlen>0) do
set @var:=concat(@var,IFNULL(ELT(1+FLOOR(RAND() * 53), 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',' ','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'),'Kedar'));
set in_strlen:=in_strlen-1;
end while;	
RETURN @var;
END $$
delimiter ;


## MySQL function to generate random Enum-ID from specified enum definition
DELIMITER $$
DROP FUNCTION IF EXISTS get_enum $$
CREATE FUNCTION get_enum(col_type varchar(100)) RETURNS VARCHAR(100) DETERMINISTIC
	RETURN if((@var:=ceil(rand()*10)) > (length(col_type)-length(replace(col_type,',',''))+1),(length(col_type)-length(replace(col_type,',',''))+1),@var);
$$
DELIMITER ;


## MySQL function to generate random float value from specified precision and scale.
DELIMITER $$
DROP FUNCTION IF EXISTS get_float $$
CREATE FUNCTION get_float(in_precision int, in_scale int) RETURNS VARCHAR(100) DETERMINISTIC
	RETURN round(rand()*pow(10,(in_precision-in_scale)),in_scale) 
$$
DELIMITER ;



## MySQL function to generate random date (of year 2012).
DELIMITER $$
DROP FUNCTION IF EXISTS get_date $$
CREATE FUNCTION get_date() RETURNS VARCHAR(10) DETERMINISTIC
	RETURN DATE(FROM_UNIXTIME(RAND() * (1356892200 - 1325356200) + 1325356200))
#	Below will generate random data for random years
#	RETURN DATE(FROM_UNIXTIME(RAND() * (1577817000 - 946665000) + 1325356200))
$$
DELIMITER ;


## MySQL function to generate random time.
DELIMITER $$
DROP FUNCTION IF EXISTS get_time $$
CREATE FUNCTION get_time() RETURNS INTEGER DETERMINISTIC
	RETURN TIME(FROM_UNIXTIME(RAND() * (1356892200 - 1325356200) + 1325356200))
$$
DELIMITER ;

## MySQL function to generate random int.
DELIMITER $$
DROP FUNCTION IF EXISTS get_int $$
CREATE FUNCTION get_int() RETURNS INTEGER DETERMINISTIC
	RETURN floor(rand()*10000000) 
$$
DELIMITER ;

## MySQL function to generate random tinyint.
DELIMITER $$
DROP FUNCTION IF EXISTS get_tinyint $$
CREATE FUNCTION get_tinyint() RETURNS INTEGER DETERMINISTIC
	RETURN floor(rand()*100) 
$$
DELIMITER ;

## MySQL function to generate random varchar column of specified length(alpha-numeric string).
DELIMITER $$
DROP FUNCTION IF EXISTS get_varchar $$
CREATE FUNCTION get_varchar(in_length varchar(500)) RETURNS VARCHAR(500) DETERMINISTIC
	RETURN SUBSTRING(MD5(RAND()) FROM 1 FOR in_length)
$$
DELIMITER ;

## MySQL function to generate random datetime value (any datetime of year 2012).
DELIMITER $$
DROP FUNCTION IF EXISTS get_datetime $$
CREATE FUNCTION get_datetime() RETURNS VARCHAR(30) DETERMINISTIC
	RETURN FROM_UNIXTIME(ROUND(RAND() * (1356892200 - 1325356200)) + 1325356200)
$$
DELIMITER ;SELECT * FROM table_name
ORDER BY RAND()
LIMIT N;
SQL相关代码片段
