Mariadb/Mysql 技巧

SELECT LPAD(n, m, 0);==>n前面补m-n个0

SELECT RPAD(n, m, 0);==>n后面补m-n个0

随机数

DELIMITER //

CREATE FUNCTION rand_num (

start_num INTEGER,

end_num INTEGER

) RETURNS INTEGER

BEGIN

RETURN FLOOR(start_num + RAND() * (end_num - start_num + 1));

END

//

DELIMITER ;

SELECT rand_num(1,10000);

concat(str1,str2,str3);==>连接字符串