欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

Mysql自定义函数

程序员文章站 2022-06-05 22:29:30
...

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。

相关标签: mysql 函数