my sql存储过程 基本使用

--------------创建不带参数的存储过程-----------------
DELIMITER;;
drop PROCEDURE if EXISTS selectStudent;
 
create PROCEDURE 'selectStudent'()
BEGIN
select*from student;
end;;
DELIMITER;
 
--------------带参数的存储过程--------------------
drop PROCEDURE if EXISTS selectCity;
 
create PROCEDURE 'selectCity'(
in _cityID varchar(10)--输入参数--
)
BEGIN
select *from student where cityID=_cityID;
end;
 
--------------带有输出参数的存储过程--------------------
drop PROCEDURE if EXISTS selectCity_Name;
CREATE PROCEDURE 'selectCity_Name'(
  in _CityID varchar(10)--输入参数,
  out _City varchar(10) --输出参数,
  inout _CityIDName varchar(10) --输入输出参数
)
BEGIN
select*from student where cityID=_CityID and CityName=_CityName INTO _City;
end;
 
set @_CityID='';
set @_CityIDName='郑州';
call selectCity_Name(@_CityID,@_City,@_CityIDName);
select @_CityIDName as ID,@_City;
 
-----------带有通配符的存储过程------------
drop PROCEDURE if EXISTS selectCityLike;
create PROCEDURE 'selectCityLike'(
in _CityName varchar(10)
)
BEGIN 
 
set @exec_sql =CONCAT("select *from student where name like '%",_CityName,"%'");
PREPARE stmt from @exec_sql ;  --定义
EXECUTE stmt;--执行预处理语句
DEALLOCATE PREPARE stmt;--删除定义
 
end
 
-------循环语句：操作前检查结果----------
create PROCEDURE proc4()
BEGIN
 
declare var int;
set var=0;
 
WHILE var<6 DO
insert into t VALUES(var);
set var=var+1;
end while;
 
end
 
----------循环语句：操作后检查结果------------
create PROCEDURE proc5()
BEGIN
 
DECLARE v int;
set v=0;
 
REPEAT
insert into t VALUES(v);
set v=v+1;
UNTIL v>=5
end repeat;
 
end
 
----------循环语句：loop..endloop------------
create PROCEDURE proc6()
BEGIN
 
declare v int;
set v=0;
 
loop_lable:LOOP
insert into values(v);
 
set v=v+1;
if v>=5 THEN
LEAVE loop_lable;
end if;
 
end loop;
 
end
 
----------循环语句：loop..endloop-------------
create PROCEDURE proc7()
BEGIN
DECLARE v int;
set v=0;
 
loop_lable:LOOP
 
if v=3 THEN
set v=v+1;
  ITERATE loop_lable;--继续循环
end if;
 
insert into t values(v);
set v=v+1;
  if v>=5 THEN
    leave loop_lable;--跳出循环
  end if;
 
end loop;
 
end;