Mysql存储过程语法

一口气弄完了！

一、条件语句if-then-else:

create procedure demo_1(in param int)
begin
declare var int;
set var=param-1;
if var=0 then
insert into userinfo(name) values('demo');
else
insert into userinfo(name) values('demo');
end if;

if param=0 then
update userinfo set age=param where name='demo';
else
update userinfo set age=1 where name='demo';
end if;
end
//

仅作语法参考并无实际意义。

二、case语句：

create procedure demo_2(in param int)
begin
case param
when 0 then
insert into userinfo(name) values('demo_0');
when 1 then
insert into userinfo(name) values('demo_1');
else
insert into userinfo(name) values('demo_default');
end case;
end
//

调用的话可以：

call demo_2(1)//

三、循环语句while-endwhile

create procedure demo_3(in param int)
begin
while param<10 do
insert into userinfo(name) values('demo');
set param=param+1;
end while;
end
//

四、repeat...end repeat：

它在执行操作后检查结果，而while则是执行前进行检查。相当于do...while

create procedure demo_4(in param int)
begin
repeat
insert into userinfo(name) values('demo');
set param=param+1;
until param>10
end repeat;
end
//

until表示满足后边的条件才继续循环

五、loop...end loop语句

create procedure demo_5(in param int)
begin
demo_5:loop
insert into userinfo(name) values('demo_5');
set param=param+1;
if param>10 then
leave demo_5;
end if;
end loop;
end
//

call demo_5(7)则输入插入4个demo_5。

六、LABLES标号：

标号可以用在begin repeat while 或者loop 语句前，语句标号只能在合法的语句前面使用。可以跳出循环，使运行指令达到复合语句的最后一步。

七、ITERATE:

通过引用复合语句的标号,来从新开始复合语句

create procedure demo_6(in param int)
begin
declare v int;
set v=0;
LOOP_LABLE:loop
if v=3 then
set v=v+1;
ITERATE LOOP_LABLE;
end if;
insert into userinfo(name) values('demo_6');
set v=v+1;
if v>=5 then
leave LOOP_LABLE;
end if;
end loop;
end
//

引：MySQL存储过程的基本函数

1、操作字符串类

CHARSET(str) //返回字串字符集

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

mysql> select substring('abcd',0,2);

+-----------------------+

| substring('abcd',0,2) |

+-----------------------+

| |

+-----------------------+

1 row in set (0.00 sec)

mysql> select substring('abcd',1,2);

+-----------------------+

| 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

2、数学类

ABS (number2 ) //绝对值

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]

注：返回类型并非均为整数，如：

(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 ) //

3、日期时间类

ADDTIME (date2 ,time_interval ) //将time_interval加到date2

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) //分返回符号,正负或0

SQRT(number2) //开平方