Mysql自定义函数
程序员文章站
2022-06-05 22:29:30
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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。