Mysql自定义函数

1.2点之间的距离

DELIMITER $$

USE `db`$$

DROP FUNCTION IF EXISTS `distance2point`$$

CREATE DEFINER=`root`@`localhost` FUNCTION `distance2point`(`lng1` DOUBLE ,`lat1` DOUBLE ,`lng2` DOUBLE ,`lat2` DOUBLE) RETURNS DOUBLE
BEGIN
	
RETURN 2 * 6378137*ASIN(SQRT(POW(SIN(PI()*(lat1-(lat2))/360),2)+ COS(PI()*lat1/180)*COS(lat2*PI()/180)*POW(SIN(PI()*(lng1-(lng2))/360),2)));
END$$

DELIMITER ;

 

2.自动生成uuid

DELIMITER $$

USE `db`$$

DROP FUNCTION IF EXISTS `MYUUID`$$

CREATE DEFINER=`root`@`localhost` FUNCTION `myuuid`() RETURNS CHAR(36) CHARSET utf8
BEGIN
DECLARE my_uuid CHAR(36);   
SET my_uuid = UUID();  
RETURN REPLACE(my_uuid,'-','_');   
END$$

DELIMITER ;

3显示城市全名称 

 根据city_type,cityCode查询

DELIMITER $$

USE `mydb`$$

DROP FUNCTION IF EXISTS `full_city_name`$$

CREATE DEFINER=`root`@`%` FUNCTION `full_city_name`(city_type INT,cityCode VARCHAR(30)) RETURNS VARCHAR(50) CHARSET utf8
BEGIN
	DECLARE pname VARCHAR(50) DEFAULT '';
  DECLARE cname VARCHAR(50) DEFAULT '';
	DECLARE aname VARCHAR(50) DEFAULT '';
	DECLARE t VARCHAR(50)  DEFAULT '';
	DECLARE t1 VARCHAR(50)  DEFAULT '';
	SELECT city_name INTO aname FROM bd_city WHERE city_code =cityCode;
	IF city_type=0 THEN  
	 SET pname=aname;
	ELSEIF city_type=1 THEN 
	SET t=SUBSTRING(cityCode,1, 2);
	 SET t1=CONCAT(t,'0000');
	 SELECT city_name INTO pname FROM bd_city WHERE city_code =t1 ;
	SET pname=CONCAT(pname,'-',aname);
	ELSEIF city_type=2 THEN 
		SET t=SUBSTRING(cityCode,1, 2);
		SET t1=CONCAT(t,'0000');
	 SELECT city_name INTO pname FROM bd_city WHERE city_code =t1 ;
	SET t=SUBSTRING(cityCode,1, 4);
	 SET t1=CONCAT(t,'00');
	 SELECT city_name INTO cname FROM bd_city WHERE city_code =t1 ;
	SET pname=CONCAT(pname,'-',cname,'-',aname);
	END IF;
	RETURN pname;
    END$$
DELIMITER ;

 根据cityId查询

DELIMITER $$

USE `mydb`$$

DROP FUNCTION IF EXISTS `full_city_name1`$$

CREATE DEFINER=`root`@`%` FUNCTION `full_city_name1`(cityId VARCHAR(36)) RETURNS VARCHAR(50) CHARSET utf8
BEGIN
	DECLARE cityType INT(1) DEFAULT 0;
	DECLARE cityCode VARCHAR(30) DEFAULT '';
	DECLARE pname VARCHAR(50) DEFAULT '';
  DECLARE cname VARCHAR(50) DEFAULT '';
	DECLARE aname VARCHAR(50) DEFAULT '';
	DECLARE t VARCHAR(50)  DEFAULT '';
	DECLARE t1 VARCHAR(50)  DEFAULT '';
	SELECT city_name,city_code,city_type INTO aname,cityCode,cityType FROM bd_city WHERE city_id =cityId;
	IF cityType=0 THEN  
	 SET pname=aname;
	ELSEIF cityType=1 THEN 
	SET t=SUBSTRING(cityCode,1, 2);
	 SET t1=CONCAT(t,'0000');
	 SELECT city_name INTO pname FROM bd_city WHERE city_code =t1 ;
	SET pname=CONCAT(pname,'-',aname);
	ELSEIF cityType=2 THEN 
		SET t=SUBSTRING(cityCode,1, 2);
		SET t1=CONCAT(t,'0000');
	 SELECT city_name INTO pname FROM bd_city WHERE city_code =t1 ;
	SET t=SUBSTRING(cityCode,1, 4);
	 SET t1=CONCAT(t,'00');
	 SELECT city_name INTO cname FROM bd_city WHERE city_code =t1 ;
	SET pname=CONCAT(pname,'-',cname,'-',aname);
	END IF;
	RETURN pname;
    END$$

DELIMITER ;

 3.汉字的首拼音组合字符串

 

DELIMITER $$

USE `mydb`$$

DROP FUNCTION IF EXISTS `getPY`$$

CREATE DEFINER=`root`@`%` FUNCTION `getPY`(in_string VARCHAR(21845)) RETURNS MEDIUMTEXT CHARSET utf8
BEGIN
DECLARE tmp_str VARCHAR(21845) CHARSET gbk DEFAULT '' ; #截取字符串，每次做截取后的字符串存放在该变量中，初始为函数参数in_string值 
DECLARE tmp_len SMALLINT DEFAULT 0;#tmp_str的长度 
DECLARE tmp_char VARCHAR(2) CHARSET gbk DEFAULT '';#截取字符，每次 left(tmp_str,1) 返回值存放在该变量中 
DECLARE tmp_rs VARCHAR(21845) CHARSET gbk DEFAULT '';#结果字符串 
DECLARE tmp_cc VARCHAR(2) CHARSET gbk DEFAULT '';#拼音字符，存放单个汉字对应的拼音首字符 
SET tmp_str = in_string;#初始化，将in_string赋给tmp_str 
SET tmp_len = LENGTH(tmp_str);#初始化长度 
WHILE tmp_len > 0 DO #如果被计算的tmp_str长度大于0则进入该while 
SET tmp_char = LEFT(tmp_str,1);#获取tmp_str最左端的首个字符，注意这里是获取首个字符，该字符可能是汉字，也可能不是。 
SET tmp_cc = tmp_char;#左端首个字符赋值给拼音字符 
IF LENGTH(tmp_char)>1 THEN#判断左端首个字符是多字节还是单字节字符，要是多字节则认为是汉字且作以下拼音获取，要是单字节则不处理。 
SELECT ELT(INTERVAL(CONV(HEX(tmp_char),16,10),0xB0A1,0xB0C5,0xB2C1,0xB4EE,0xB6EA,0xB7A2,0xB8C1,0xB9FE,0xBBF7,0xBFA6,0xC0AC 
,0xC2E8,0xC4C3,0xC5B6,0xC5BE,0xC6DA,0xC8BB,0xC8F6,0xCBFA,0xCDDA ,0xCEF4,0xD1B9,0xD4D1), 
'A','B','C','D','E','F','G','H','J','K','L','M','N','O','P','Q','R','S','T','W','X','Y','Z') INTO tmp_cc; #获得汉字拼音首字符 
END IF; 
SET tmp_rs = CONCAT(tmp_rs,tmp_cc);#将当前tmp_str左端首个字符拼音首字符与返回字符串拼接 
SET tmp_str = SUBSTRING(tmp_str,2);#将tmp_str左端首字符去除 
SET tmp_len = LENGTH(tmp_str);#计算当前字符串长度 
END WHILE; 
RETURN tmp_rs;#返回结果字符串 
END$$

DELIMITER ;

 

 

总结：使用DELIMITER定义结束字符$$，因为sql语句中使用了分号符;，所以定义use,drop,end等语句的时候，也需要结束符号。所以用DELIMITER定义结束字符。