1、數據存儲：把多個sql語句封裝成一個方法


delimiter //    修改結束符
create procedure proc()
begin  
select * from student;
end
//
call  調用方法

變量的定義：
declare 變量名  type  default 默認值；
修改變量的值
set 變量名= 值 或 



Drop  procedure proc2;
delimiter //
Create procedure proc2()
Begin 
Declare var1 varchar(10) default null;
Declare var2 int
 
  default 0;
select name ,age into  var1, var2 from student where id =1; 
         Result consisted of more than one row(這種錯誤出現的原因是沒指定id 的值，結果多余變量的個數)
Select var1;
Select var2;
End  //
Delimiter ;


delimiter //
drop procedure if exists proc2;
Create procedure proc2()
Begin 
Declare var1 varchar(10) default
 
 null;
declare var2   int  default 0;
select name ,age into  var1, var2 from student where id =1; 
Select var1 as  姓名, var2 as 年齡;
End  //
Delimiter ;

1、存儲過程：
Delimiter //    修改結束符
Drop  procedure if exists pro1;     判斷，如果存在pro1 則刪除
Create  procedure pro1()     創建 procedure 存儲過程
Begin 
End//
Delimiter ;
Call pro1;



 
2、遊標：

語法：
(
    聲明遊標
    declare cursor_name cursor for select_statement;
    打開遊標（在使用遊標之前）
    open cursor_name;
    獲取遊標中的數據 into 變量
    fetch cursor_name into var_name1,var_name2,...;
    關閉遊標（在使用遊標之後）
    close cursor_name;
)
 
 
 delimiter //
 drop procedure if exists pro;
 create procedure pro()
     begin
     declare var varchar(20) default null;
     declare cursor_name cursor for select name from student where id=1;
     open cursor_name;
     fetch cursor_name into var;
     close cursor_name;
     select var as 姓名;
     end //
 delimiter ;
 call pro;




procedure  程序、declare  聲明、
delimiter //
Drop procedure if exists pro//
create procedure pro()
begin 
declare  var1  char(10) default null;
declare  var2  int  default 0;
declare  cursor1 cursor for select name ,age  from student where id=1;    
open cursor1;
fetch cursor1 into var1, var2;
close cursor1;
select var1 as ‘姓名’, var2 as ‘年齡’;
end  //
delimiter ;
call pro;




3、存儲過程中的if判斷語句

語法：
(
    if ..... then ......;
    else if ...... then ......;
    else .......;
    end if;
)


delimiter //
drop procedure if exists pro//
Create procedure pro()
begin 
declare var int;
if var is null then select ‘var is null‘ as 結果;
Else select var as 結果;
end if;
Set var=10;
If var is null then select  ‘var is null‘ as 結果;
Else select var  as 結果;
End if;
End//
Delimiter ;
Call pro;


4、存儲過程中的case判斷語句

語法：
(
    case  要判斷的變量
    when .... then .... ;
    when .... then .... ;
    ....;
    else ....;
    end case;
)


 delimiter //
 drop procedure if exists pro;
 create procedure pro()
     begin
     declare var int default 0;
     set var=5;
     case var
     when 1 then select * from student where id=var;
     when 2 then select * from student where id=var;
     when 3 then select * from student where id=var;
     else select ‘no such case‘ as 結果;
     end case;
     end//
 delimiter ;
 call pro;
 
 
 
 5、存儲過程中的loop循環語句
 
 語法：
 (
     loop sql_statement;
         if ... then leave/iterate;
         end if;
     end loop;
 )
 
 
 delimiter //
 drop procedure if exists pro//
 create procedure pro()
     begin
     declare var int default 0;
     myloop:loop insert student values(null,‘Rose‘,var,‘女‘);
          if var >=100 then leave myloop;
          end if;
          set var=var+1;
     end loop;
     end//
 delimiter ;
 call pro;
 
 註意：在sql語句中沒有 “==”，直接用“=”來作為判斷等於的符號。
 

 
 6、存儲過程中的repeat循環語句
 
 語法：
 (
     repeat_label:repeat sql_statement;
     until ... end repeat repeat_label;
     
 )

 
 delimiter //
 select * from student//
 drop procedure if exists pro;
 create procedure pro()
 begin
 declare var int default 1;
 my_repeat:repeat insert into student values(null,‘Rose‘,var,‘女‘);
 set var=var+1;
 until var>100 end repeat my_repeat;
 end//
 delimiter ;
 call pro;
 select * from student;
 
 
 
 7、存儲過程中的while循環
 
 語法：
 (
     while_label：while ...(循環條件)
     do sql_statement;
     end while while_label;
 )
 
 
 delimiter //
 select * from student//
 drop procedure if exists pro//
 create procedure pro()
 begin
 declare var int default 719;
 my_while:while var<=818
 do delete from student where id = var;
 set var=var+1;
 end while my_while;
 end//
 delimiter ;
 call pro;
 
 
 
 delimiter //
 drop procedure if exists pro//
 create procedure pro()
 begin
 declare var int default 1;
 my_while:while var<=100
 do insert into student values(null,‘Rose‘,var,‘女‘);
 set var=var+1;
 end while my_while;
 end//
 delimiter ;
 call pro;
 
 
 8、查看存儲過程
 
 語法：
 (
     show {procedure/function} status [like ‘pattern‘];
     show create procedure pro_name;
 )
 
 show procedure status;
 show create procedure pro;
 
 
 
 9、修改存儲過程
 
 
 10、刪除存儲過程
  語法：
  (
      drop {procedure/function} if exists pro_name;
  )
 
  drop procedure if exists pro;
 
 
 
  11、存儲過程出錯處理
  
  定義錯誤情況
  
  declare condition_name condition for condition_type;

mysql-存儲過程