Mysql存储过程知识,案例:
create procedure delete_setting(in p_settingid integer) begin delete from setting where settingid=p_settingid; end select `name` from mysql.proc where db = 'your_db_name' and `type` = 'PROCEDURE' show procedure status; show create procedure proc_name; show create function func_name; 局部变量 create procedure test3(out number1 integer) begin declare number2 integer default 100; set number1=number2; end call test(@number) select @number# 默认值为标量子查询 create procedure test2(out ta integer) begin declare tt integer default (select count(*) from `setting`); set ta=tt; end 流程控制 IF create procedure getMax(in p1 integer,in p2 integer,out p3 integer) begin if p1>p2 then set p3 = p1; elseif p1<p2 then set p3 = p2; else set p3=0; end if; end fibonnaci create procedure fibonnaci(inout n1 integer,inout n2 integer,inout n3 integer) begin set n3=n1+n2; if n3>1000 then set n3 = n3-1000; end if; set n1=n2; set n2=n3; end create procedure largest(out t char(30)) begin if (select count(*) from product)>(select count(*) from productcategory) then set t="product"; elseif (select count(*) from product)<(select count(*) from productcategory) then set t="productcategory"; else set t = "equal"; end if; end create procedure small_exit(out p1 integer,out p2 integer) begin set p1 = 1; set p2 = 2; block1:begin leave block1; set p2 = 3; end; set p1=4; end WHILE 计算两个相差的年月日 create procedure age( in start_date date, in end_date date, out years integer, out monthes integer, out days integer ) begin declare next_date,previous_date date; set years = 0; set previous_date=start_date; set next_date =start_date+interval 1 year; while next_date<end_date do set years = years+1; set previous_date = next_date; set next_date = next_date+ interval 1 year; end while; set monthes = 0; set next_date = previous_date + interval 1 month; while next_date<end_date do set monthes = monthes +1; set previous_date=next_date; set next_date = previous_date+interval 1 month; end while; end ———————————————————————— 调用存储过程 建表 create table players_with_parents (playerno integer not null primary key, father_playerno integer, mother_playerno integer); alter table players_with_parents add constraint fk_1 foreign key (father_playerno) references player_with_parents (playerno); alter table players_with_parents add foreign key (mother_playerno) references player_with_parents(playerno); 增加外键约束; insert into players_with_parents values(9,null,null),(8,null,null),(7,null,null),(6,null,null),(5,null,null) ,(4,8,9),(3,6,7),(2,4,5),(1,2,3) create procedure total_number_of_parents(in_playerno integer,inout number integer) begin declare v_father,v_mother integer; set v_father = (select father_playerno from players_with_parents where playerno=in_playerno); set v_mother = (select mother_playerno from players_with_parents where playerno=in_playerno); if v_father is not null then call total_number_of_parents(v_father,number); set number = number+1; end if; if v_mother is not null then call total_number_of_parents(v_mother,number); set number = number+1; end if; end set @num=0; set max_sp_recursion_depth=100; call total_number_of_parents(4,@num); select @num; select into create procedure total_setting(out p1 integer) begin select count(*) into p1 from `setting`; end create procedure get_setting(out v_name varchar(60),out v_value varchar(60)) begin select `name`,`value` into v_name,v_value from setting limit 0,1; end create procedure showErr(out p integer) begin set p=1; insert into `setting` (`settingid`,`name`)values(12,'vname'); set p=2; end create procedure showErr(out p integer,out error integer) begin declare continue handler for sqlstat '23000' set error = '200000'; declare continue handler for sqlstat '23001'; set error = '200001'; set error = '000000'; set p=1; insert into `setting` (`settingid`,`name`)values(12,'vname'); set p=2; end declare continue handler for 1062 set error='23000'; declare continue handler for 1136 set error='21S01'; 01 SQLWARING 02 NOT FOUND SQLEXCEPTION 01,02以外的 create procedure addDate(out error char(5)) begin declare continue handler for sqlstate '23000' set error='23000'; declare continue handler for sqlstate '21S01' set error='21S01'; set error='00000'; insert into `setting` values(15,'test','testValue',10); end declare non_unique condition for sqlstate '23000'; ddeclare continue handler for non_unique set error='23000'; 同一块中,相同的错误,不能有两个或多个处理程序; 带有游标的存储过程 declare c_players cursor for select playerno from players; create procedure number_of_players(out number integer) begin declare a_playerno integer; declare found boolean default true; declare c_players cursor for select playerno from players; declare continue handler for not found set found=false; set number=0; open c_players; fetch c_players into a_playerno; while found do set number =number+1; fetch c_players into a_playerno; end while; close c_players; end create procedure number_of_setting(out number integer) begin declare a_settingid integer; declare found boolean default true; declare c_settingids cursor for select settingid from setting; declare continue handler for not found set found=false; set number=0; open c_settingids; fetch c_settingids into a_settingid; while found do set number=number+1; fetch c_settingids into a_settingid; end while; close c_settingids; end create procedure delete_older_than_30() begin declare v_age,v_playerno,v_years,v_months,v_days integer; declare v_birth_date date; declare found boolean default true; declare c_players cursor for select playerno,birth_date from players; declare continue handler for not found set found=false; open c_players; fetch c_players into v_playerno,v_birth_date; while found do call age(v_birth_date,now(),v_years,v_months,v_days); if v_years>30 then delete from penalties where playerno=v_playerno; end if; fetch c_players into v_playno,v_birth_date; end while; close c_players; end commit,rollback,start transaction; create function test(t1 integer,t2 integer) returns integer begin return t1+t2; end
查询数据库中的存储过程
方法一:
select `name` from mysql.proc where db = 'your_db_name' and `type` = 'PROCEDURE'
方法二:
show procedure status;
查看存储过程或函数的创建代码
show create procedure proc_name;
show create function func_name;
查询数据库中的存储过程和函数
方法一:
select `name` from mysql.proc where db = 'your_db_name' and `type` = 'PROCEDURE' //存储过程
select `name` from mysql.proc where db = 'your_db_name' and `type` = 'FUNCTION' //函数
方法二:
show procedure status; //存储过程
show function status; //函数
查看存储过程或函数的创建代码
show create procedure proc_name;
show create function func_name;
查看视图
SELECT * from information_schema.VIEWS //视图
SELECT * from information_schema.TABLES //表
查看触发器
方法一:
语法:SHOW TRIGGERS [FROM db_name] [LIKE expr]
实例:SHOW TRIGGERSG //触发器
方法二:
对INFORMATION_SCHEMA数据库中的TRIGGERS表查询
mysql>SELECT * FROM triggers T WHERE trigger_name=”mytrigger” G
在存儲過程中使用 表名做变量传递:
PREPARE stmt_name FROM preparable_stmt; EXECUTE stmt_name [USING @var_name [, @var_name] ...]; {DEALLOCATE | DROP} PREPARE stmt_name;
下面是示例:
DROP PROCEDURE IF EXISTS `newtable`; CREATE PROCEDURE `newtable`(IN tname varchar(64)) BEGIN SET @sqlcmd = CONCAT('CREATE TABLE ', tname, ' (id int NOT NULL AUTO_INCREMENT, name varchar(64) DEFAULT NULL, PRIMARY KEY (`id`))'); PREPARE stmt FROM @sqlcmd; EXECUTE stmt; DEALLOCATE PREPARE stmt; END; call newtable('abc');
再来一个示例:
create procedure ate(in t char(30)) begin set @s=concat("alter table ",t," engine=innodb"); prepare stmt from @s; execute stmt; deallocate prepare stmt; end call ate('deal')#
看下面的示例:
mysql> SET @s = 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse'; mysql> PREPARE stmt2 FROM @s; mysql> SET @a = 6; mysql> SET @b = 8; mysql> EXECUTE stmt2 USING @a, @b; +------------+ | hypotenuse | +------------+ | 10 | +------------+ mysql> DEALLOCATE PREPARE stmt2;
在sql中替换变量;
如果你的MySQL 版本是 5.0.7 或者更高的,你还可以在 LIMIT 子句中使用它,示例如下:
mysql> SET @a=1;mysql> PREPARE STMT FROM "SELECT * FROM tbl LIMIT ?"; mysql> EXECUTE STMT USING @a; mysql> SET @skip=1; SET @numrows=5; mysql> PREPARE STMT FROM "SELECT * FROM tbl LIMIT ?, ?"; mysql> EXECUTE STMT USING @skip, @numrows;
使用 PREPARE 的几个注意点:
A:PREPARE stmt_name FROM preparable_stmt;预定义一个语句,并将它赋给 stmt_name ,tmt_name 是不区分大小写的。
B: 即使 preparable_stmt 语句中的 ? 所代表的是一个字符串,你也不需要将 ? 用引号包含起来。
C: 如果新的 PREPARE 语句使用了一个已存在的 stmt_name ,那么原有的将被立即释放! 即使这个新的 PREPARE 语句因为错误而不能被正确执行。
D: PREPARE stmt_name 的作用域是当前客户端连接会话可见。
E: 要释放一个预定义语句的资源,可以使用 DEALLOCATE PREPARE 句法。
F: EXECUTE stmt_name 句法中,如果 stmt_name 不存在,将会引发一个错误。
G: 如果在终止客户端连接会话时,没有显式地调用 DEALLOCATE PREPARE 句法释放资源,服务器端会自己动释放它。
H: 在预定义语句中,CREATE TABLE, DELETE, DO, INSERT, REPLACE, SELECT, SET, UPDATE, 和大部分的 SHOW 句法被支持。
I: PREPARE 语句不可以用于存储过程,自定义函数!但从 MySQL 5.0.13 开始,它可以被用于存储过程,仍不支持在函数中使用!
了解了PREPARE的用法,再用变量做表名就很容易了。不过在实际操作过程中还发现其他一些问题,比如变量定义,declare变量和set @var=value变量的用法以及参数传入的变量。
测试后发现,set @var=value这样定义的变量直接写在字符串中就会被当作变量转换,declare的变量和参数传入的变量则必须用CONCAT来连接。具体的原理没有研究。
EXECUTE stmt USING @a;这样的语句USING后面的变量也只能用set @var=value这种,declare和参数传入的变量不行。
另外php调用mysql存储过程的时候也碰到很多问题,总是出现PROCEDURE p can't return a result set in the given context这样的问题。
mysql存储过程基本函数
一.字符串类
CONCAT (string2 [,... ]) //连接字串
INSTR (string ,substring ) //返回substring首次在string中出现的位置,不存在返回0
LCASE (string2 ) //转换成小写
LEFT (string2 ,length ) //从string2中的左边起取length个字符
LENGTH (string ) //string长度
LOAD_FILE (file_name ) //从文件读取内容
LOCATE (substring , string [,start_position ] ) 同INSTR,但可指定开始位置
LPAD (string2 ,length ,pad ) //重复用pad加在string开头,直到字串长度为length
LTRIM (string2 ) //去除前端空格
REPEAT (string2 ,count ) //重复count次
REPLACE (str ,search_str ,replace_str ) //在str中用replace_str替换search_str
RPAD (string2 ,length ,pad) //在str后用pad补充,直到长度为length
RTRIM (string2 ) //去除后端空格
STRCMP (string1 ,string2 ) //逐字符比较两字串大小,
SUBSTRING (str , position [,length ]) //从str的position开始,取length个字符,
注:mysql中处理字符串时,默认第一个字符下标为1 ,即参数position必须大于等于1
+———————–+
| substring(’abcd’,0,2) |
+———————–+
| |
+———————–+
1 row in set (0.00 sec)
+———————–+
| substring(’abcd’,1,2) |
+———————–+
| ab |
+———————–+
1 row in set (0.02 sec)
TRIM([[BOTH|LEADING|TRAILING] [padding] FROM]string2) //去除指定位置的指定字符
UCASE (string2 ) //转换成大写
RIGHT(string2,length) //取string2最后length个字符
SPACE(count) //生成count个空格
二.数学类
BIN (decimal_number ) //十进制转二进制
CEILING (number2 ) //向上取整
CONV(number2,from_base,to_base) //进制转换
FLOOR (number2 ) //向下取整
FORMAT (number,decimal_places ) //保留小数位数
HEX (DecimalNumber ) //转十六进制
注:HEX()中可传入字符串,则返回其ASC-11码,如 HEX(’DEF’)返回4142143
也可以传入十进制整数,返回其十六进制编码,如HEX(25)返回19
LEAST (number , number2 [,..]) //求最小值
MOD (numerator ,denominator ) //求余
POWER (number ,power ) //求指数
RAND([seed]) //随机数
ROUND (number [,decimals ]) //四舍五入,decimals为小数位数]
(1)默认变为整形值
mysql> select round(1.23);
+————-+
| round(1.23) |
+————-+
| 1 |
+————-+
1 row in set (0.00 sec)
mysql> select round(1.56);
+————-+
| round(1.56) |
+————-+
| 2 |
+————-+
1 row in set (0.00 sec)
(2)可以设定小数位数,返回浮点型数据
mysql> select round(1.567,2);
+—————-+
| round(1.567,2) |
+—————-+
| 1.57 |
+—————-+
1 row in set (0.00 sec)
SIGN (number2 ) //返回符号,正负或0
SQRT(number2) //开平方
三.日期时间类
CONVERT_TZ (datetime2 ,fromTZ ,toTZ ) //转换时区
CURRENT_DATE ( ) //当前日期
CURRENT_TIME ( ) //当前时间
CURRENT_TIMESTAMP ( ) //当前时间戳
DATE (datetime ) //返回datetime的日期部分
DATE_ADD (date2 , INTERVAL d_value d_type ) //在date2中加上日期或时间
DATE_FORMAT (datetime ,FormatCodes ) //使用formatcodes格式显示datetime
DATE_SUB (date2 , INTERVAL d_value d_type ) //在date2上减去一个时间
DATEDIFF (date1 ,date2 ) //两个日期差
DAY (date ) //返回日期的天
DAYNAME (date ) //英文星期
DAYOFWEEK (date ) //星期(1-7) ,1为星期天
DAYOFYEAR (date ) //一年中的第几天
EXTRACT (interval_name FROM date ) //从date中提取日期的指定部分
MAKEDATE (year ,day ) //给出年及年中的第几天,生成日期串
MAKETIME (hour ,minute ,second ) //生成时间串
MONTHNAME (date ) //英文月份名
NOW ( ) //当前时间
SEC_TO_TIME (seconds ) //秒数转成时间
STR_TO_DATE (string ,format ) //字串转成时间,以format格式显示
TIMEDIFF (datetime1 ,datetime2 ) //两个时间差
TIME_TO_SEC (time ) //时间转秒数]
WEEK (date_time [,start_of_week ]) //第几周
YEAR (datetime ) //年份
DAYOFMONTH(datetime) //月的第几天
HOUR(datetime) //小时
LAST_DAY(date) //date的月的最后日期
MICROSECOND(datetime) //微秒
MONTH(datetime) //月
MINUTE(datetime) //分
DAY ,DAY_HOUR ,DAY_MINUTE ,DAY_SECOND ,HOUR ,HOUR_MINUTE ,HOUR_SECOND ,MINUTE ,MINUTE_SECOND,MONTH ,SECOND ,YEAR
" SELECT `table_name` FROM `information_schema`.`TABLES` WHERE `TABLE_SCHEMA`= 'banksys'"
-- 将电商domain查询,格式化,查询是否有,没有则增加,更新资讯 drop PROCEDURE if EXISTS `mall_domain_format`; CREATE PROCEDURE mall_domain_format() BEGIN declare a_mall_id,target_mall_id,number,affect_number,target_is_abroad integer; DECLARE a_domain,format_domain varchar(255); declare found boolean DEFAULT true; DECLARE mall_cursor cursor for select mall_id,domain from `wlt_mall` order by mall_id asc; declare CONTINUE HANDLER for not found set found=false; open mall_cursor; fetch mall_cursor into a_mall_id,a_domain; set number = 0; -- select found; while found DO set number = number+1; -- select a_mall_id,a_domain; -- 格式化a_domain -- 查找是否存在 该电商 -- 存在则更新 ;不存在则插入,更新 set format_domain = format_domain(a_domain); -- select format_domain; select mall_id into target_mall_id from `wlt_mall` where domain=format_domain limit 1; -- select target_mall_id,format_domain,a_mall_id; if ISNULL(target_mall_id) THEN INSERT INTO `wlt_mall` (`mall_id`, `mall_name`, `domain`) VALUES (null, '', format_domain); -- SELECT LAST_INSERT_ID() into target_mall_id; -- select 'insert into run',target_mall_id; end if; select mall_id,is_abroad into target_mall_id,target_is_abroad from `wlt_mall` where domain=format_domain limit 1; -- select 'not run insert into',target_mall_id; if target_mall_id != a_mall_id THEN -- select concat('select count(1) into affect_number from zx_article where mall_id=',a_mall_id,';'); -- select concat('update zx_article set mall_id=',target_mall_id,' where mall_id=',a_mall_id); -- select concat('select count(1) into affect_number from zx_article where mall_id=',a_mall_id,';'); select count(1) into affect_number from zx_article where mall_id=a_mall_id; -- SELECT a_mall_id,affect_number,'hehe'; update zx_article set mall_id=target_mall_id,is_abroad=target_is_abroad where mall_id=a_mall_id; update wlt_mall set article_number=article_number+affect_number where mall_id=target_mall_id; delete from wlt_mall where mall_id=a_mall_id; -- select 'run merge',target_mall_id,a_mall_id; end IF; fetch mall_cursor into a_mall_id,a_domain; end while; close mall_cursor; select number; END call mall_domain_format(); select * FROM zx_article where mall_id=337; select * from wlt_mall where mall_id=337; select * from wlt_mall where domain like '%ba.de%'; -- 386 select count(1) from `wlt_mall` order by mall_id asc; INSERT INTO `walatao_info`.`wlt_mall` (`mall_id`, `mall_name`, `domain`, `country`, `is_abroad`, `introduce`, `comment`, `logo`, `article_number`, `product_number`, `display_order`, `status`) VALUES (null, 'm.taobao.com', 'm.taobao.com', '', '0', '', '', '', '1', '0', '0', '1'); drop function if EXISTS format_domain; create function format_domain(domain varchar(255)) returns varchar(255) BEGIN -- 替换掉http:// https://,替换掉/ 查找最后出现的.,查找倒数第二个点 declare return_str varchar(255) default ''; declare source_domain VARCHAR(255) DEFAULT ''; declare flag TINYINT(1) DEFAULT 0; set domain = LTRIM(domain); set domain = RTRIM(domain); set domain = REPLACE(domain,'http://',''); set domain = REPLACE(domain,'https://',''); set domain = REPLACE(domain,'/',''); set source_domain = LOWER(domain); set domain = SUBSTRING_INDEX(domain, '.', -2); case domain when 'com.cn' THEN set flag = 1; when 'com.hk' THEN set flag = 1; when 'net.cn' THEN set flag = 1; when 'com.au' THEN set flag = 1; when 'co.nz' THEN set flag = 1; when 'co.uk' THEN set flag = 1; when 'co.jp' THEN set flag = 1; when 'cn.com' THEN set flag = 1; ELSE set flag = 0; end case; if flag=1 then set return_str = SUBSTRING_INDEX(source_domain, '.', -3); ELSE set return_str = domain; end if; return return_str; END
在上面的Sql中有个地方需要注意:如果在循环中如有select...into... from table....;结构的语句,会将continue handler标志重置成该sql的标志。会使循环不准。
导致的结果是外层循环还没有结束,里面的continue handler的标志的值就为0了,不满足循环。以下是对该功能的改版。
select count(1) 不会有这种情况。这可能是mysql的bug。
-- 将电商domain查询,格式化,查询是否有,没有则增加,更新资讯 drop PROCEDURE if EXISTS `mall_domain_format`; CREATE PROCEDURE mall_domain_format() BEGIN declare a_mall_id,target_mall_id,number,affect_number,target_is_abroad,insert_target_mall_id,format_domain_number integer DEFAULT 0; DECLARE a_domain,format_domain varchar(255); declare found boolean DEFAULT true; DECLARE mall_cursor cursor for select mall_id,domain from `wlt_mall` order by mall_id asc; declare CONTINUE HANDLER for not found set found=false; open mall_cursor; fetch mall_cursor into a_mall_id,a_domain; set number = 0; -- select found; while found DO set number = number+1; set target_mall_id = null; set format_domain=null; set format_domain_number = 0; -- select a_mall_id,a_domain; -- 格式化a_domain -- 查找是否存在 该电商 -- 存在则更新 ;不存在则插入,更新 set format_domain = format_domain(a_domain); -- select format_domain; select count(1) into format_domain_number from `wlt_mall` where domain=format_domain limit 1; -- select target_mall_id,format_domain,a_mall_id; if format_domain_number=0 THEN INSERT INTO `wlt_mall` (`mall_id`, `mall_name`, `domain`) VALUES (null, '', format_domain); -- SELECT LAST_INSERT_ID() into insert_target_mall_id; -- select 'insert into run',target_mall_id; end if; -- debug /* if format_domain='rakuten.com' || target_mall_id is NULL || a_mall_id is NULL || number=7 || number=8 || number=9 THEN -- SELECT target_mall_id,format_domain,a_mall_id,'a',found; select mall_id,is_abroad into target_mall_id,target_is_abroad from `wlt_mall` where domain=format_domain limit 1; -- SELECT target_mall_id,format_domain,a_mall_id,'b',found; INSERT INTO `error_log` (`error_id`, `error_log`) VALUES (null, concat('insert_target_mall_id:',insert_target_mall_id,' target_mall_id:',target_mall_id,' format_domain:',format_domain)); end if; */ select mall_id,is_abroad into target_mall_id,target_is_abroad from `wlt_mall` where domain=format_domain limit 1; -- end debug -- select 'not run insert into',target_mall_id; if target_mall_id != a_mall_id THEN -- select concat('select count(1) into affect_number from zx_article where mall_id=',a_mall_id,';'); -- select concat('update zx_article set mall_id=',target_mall_id,' where mall_id=',a_mall_id); -- select concat('select count(1) into affect_number from zx_article where mall_id=',a_mall_id,';'); select count(1) into affect_number from zx_article where mall_id=a_mall_id; -- SELECT a_mall_id,affect_number,'hehe'; update zx_article set mall_id=target_mall_id,is_abroad=target_is_abroad where mall_id=a_mall_id; update wlt_mall set article_number=article_number+affect_number where mall_id=target_mall_id; delete from wlt_mall where mall_id=a_mall_id; -- select 'run merge',target_mall_id,a_mall_id; end IF; fetch mall_cursor into a_mall_id,a_domain; end while; close mall_cursor; select number,a_mall_id,a_domain,found,format_domain,target_mall_id; END