2)case语句

mysql > DELIMITER //

mysql >CREATEPROCEDUREproc3 (inparameterint)

->begin

->declarevarint;

->setvar=parameter+1;

->casevar

->when0then

->insertintotvalues(17);

->when1then

->insertintotvalues(18);

->else

->insertintotvalues(19);

->endcase;

->end;

-> //

mysql > DELIMITER ;

4.6.2循环语句

1)while ···· end whilemysql > DELIMITER //

mysql >CREATEPROCEDUREproc4()

->begin

->declarevarint;

->setvar=0;

-> while var<6 do

->insertintotvalues(var);

->setvar=var+1;

->endwhile;

->end;

-> //

mysql > DELIMITER ;

2)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。mysql > DELIMITER //

mysql >CREATEPROCEDUREproc5 ()

->begin

->declarevint;

->setv=0;

-> repeat

->insertintotvalues(v);

->setv=v+1;

-> until v>=5

->endrepeat;

->end;

-> //

mysql > DELIMITER ;

3)loop ·····end loop：loop循环不需要初始条件，这点和while循环相似，同时和repeat循环一样不需要结束条件, leave语句的意义是离开循环。

[begin_label:]LOOP

statement_list

END LOOP [end_label]

mysql > DELIMITER //

mysql >CREATEPROCEDUREproc6 ()

->begin

->declarevint;

->setv=0;

-> LOOP_LABLE:loop

->insertintotvalues(v);

->setv=v+1;

-> if v >=5then

-> leave LOOP_LABLE;

->endif;

->endloop;

->end;

-> //

mysql > DELIMITER ;

4.6.3LEAVE语句：跳出循环控制

LEAVE label

注：label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。

4.6.4ITERATE迭代：通过引用复合语句的标号,跳出本次循环，执行下一轮。mysql > DELIMITER //

mysql >CREATEPROCEDUREproc10 ()

->begin

->declarevint;

->setv=0;

-> LOOP_LABLE:loop

-> if v=3then

->setv=v+1;

-> ITERATELOOP_LABLE;

->endif;

->insertintotvalues(v);

->setv=v+1;

-> if v>=5then

-> leave LOOP_LABLE;

->endif;

->endloop;

->end;

-> //

mysql > DELIMITER ;

4.7MySQL存储过程的基本函数

(1).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 ) //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 ) //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) //RPAD (string2 ,length ,pad) //在str后用pad补充,直到长度为length

RTRIM (string2 ) //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例：

mysql>selectsubstring('abcd',0,2);

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

|substring('abcd',0,2) |

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

| |

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

1 rowinset(0.00 sec)

mysql>selectsubstring('abcd',1,2);

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

|substring('abcd',1,2) |

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

| ab |

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

1 rowinset(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 [,..]) //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>selectround(1.23);

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

| round(1.23) |

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

| 1 |

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

1 rowinset(0.00 sec)

mysql>selectround(1.56);

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

| round(1.56) |

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

| 2 |

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

1 rowinset(0.00 sec)

(2)可以设定小数位数，返回浮点型数据mysql>selectround(1.567,2);

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

| round(1.567,2) |

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

| 1.57 |

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

1 rowinset(0.00 sec)

(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