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  • Mysql存储过程简明使用

    mysql> d //  改变命令行下的结束符标志
    mysql> create procedure p3()
    -> begin
    -> set @i=1;  # 这样也可以定义变量变给值
    -> while @i<10000 do
    -> insert into t3 values (@i);
    -> set @i=@i+1;
    -> end while;
    -> end //


    1.存储过程创建语法
    create procedure 存储过程名称()
    begin
    -- sql语句
    end;

    2.查看已有的存储过程
    show procedure status;

    3.调用存储过程
    call 存储过程名称();

    4.在存储过程中申明变量 declare
    --格式 declare 变量名 变量类型 [default 默认值]
    create procedure p2()
    begin
    declare age smallint default 18;
    declare hi int smallint default 180;
    select concat('年龄是:',age,'身高为:',hi);
    end;

    --运算和赋值
    -- set 变量名 := expression
    create procedure p3()
    begin
    declare age smallint default 18;
    declare hi int smallint default 180;
    set age := age+20;
    select concat('年龄是:',age,'身高为:',hi);
    end;

    -- if/else控制结构
    /**
    if condition then
    执行语句
    else
    end if;
    */
    create procedure p4()
    begin
    declare age smallint default 18;
    declare hi int smallint default 180;
    if age>=18 then
    select '成年';
    else
    select '很小';
    end if;
    end;

    -- 存储过程传参
    /**
    存储过程的括号里,可以声明参数
    语法[in/out/inout] 参数名 参数类型
    */
    create procedure p5(width int,height int)
    begin
    select width+height;
    end;
    call p5(10,20);

    --循环
    --求1到100之和
    create procedure p6()
    begin
    declare sum smallint default 0;
    declare i smallint default 0;
    while i<=100 do
    set sum := sum+i;
    set i := i+1;
    end while;
    select sum;
    end;
    call p6();

    create procedure p7(in n int)
    begin
    declare sum smallint default 0;
    declare i smallint default 0;
    while i<=n do
    set sum := sum+i;
    set i := i+1;
    end while;
    select sum;
    end;
    call p7(100);


    -- out 类型参数
    create procedure p8(in n int,out total int)
    begin
    declare num int default 0;
    set total := 0;
    while num<n do
    set num := num+1;
    set total := total+num;
    end while;
    end;
    call p8(100,@sum);
    select @sum;

    --inout类型
    create procedure p9(inout age int)
    begin
    set age := age+20;
    end;
    set @currAge = 18;
    call p9(@currAge);
    select @currAge;

    -- case用法
    create procedure p10()
    begin
    declare pos int default 0;
    set pos := floor(5*rand());
    case pos
    when 1 then select '小明';
    when 2 then select '小华';
    when 3 then select '小张';
    else select '未知';
    end case;
    end;
    call p10();

    -----repeat 循环
    /*
    repeat
    sql语句;
    .....
    sqlN;
    until condition end repeat;
    */
    create procedure p11()
    begin
    declare i int default 0;
    declare sum int default 0;
    repeat
    set i := i+1;
    set sum := sum+i;
    until i>=100 end repeat;
    select sum;
    end;

    ##########################################################

    1.查看存储过程
    show procedure status;

    2.删除存储过程
    drop procedure 存储过程名称

    3.创建存储过程

     1 create procedure p1()
     2 begin
     3 select * from table;
     4 end;
     5 
     6 call p1();
     7 
     8 create procedure p2(n int)
     9 begin
    10 select * from table where num>n;
    11 end;
    12 
    13 call p2(2);
    14 
    15 
    16 create procedure p3(n int,j char(1))
    17 begin
    18     if j='a' then
    19         select * from table where num>n;
    20     else
    21         select * from table where num<n;
    22     end if;
    23 end;
    24 
    25 call p3(2,'a');
    26 
    27 
    28 #计算1->n的和
    29 create procedure p4(n smallint)
    30 begin
    31     declare i int;
    32     declare sum int;
    33     set i = 1;
    34     set sum = 0;
    35     while i <= n do
    36         set sum = sum+i;
    37         set i = i+1;
    38     end while;
    39     select sum;
    40 end;
    41 call p4(100);

    4.调用存储过程
    call 存储过程名称();

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  • 原文地址:https://www.cnblogs.com/ahwu/p/3617901.html
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