[MySQL]存储过程

存储过程语法：

create procedure procedureName
begin
sql 1
end$

显示所有的存储过程   show procedure status;
调用存储过程            call procedureName();

包含if语句的存过：
create procedure procedureName()
begin
declare yy int
if
sql1
else
sql2
end if;
end$

案例：

create procedure procedureName(width int,height int)
begin
select concat(‘你的面积是‘,width*height) as  area;
if width >height then
select ‘你挺胖‘;
elseif width <height then
select ‘你挺瘦‘；
else
select ‘你挺方‘;
end if;
end$

编程三步骤
顺序 选择 循环

while循环语句的存过：
求1到100的和；
delimiter $
create procedure procedurename ()
begin
declare total int default 0;
declare num2 int default 0;
while num2<=100  do
set total:=total+num2;
set num2:=num2+1;
end while;
select total;
end$

in/out/inout

--in传入参数
create procedure name (in num int)
begin
declare total int default 0;
declare num2 int default 0;
while num2<=num  do
set total:=total+num2;
set num2:=num2+1;
end while;
select total;
end$

--in/out
delimiter$
create procedure p8 (in num int,out total int )
begin
declare num2 int default 0;
set total :=0;
while num2<=num  do
set total:=total+num2;
set num2:=num2+1;
end while;
select total;
end$
调用方法：
call p8(100,@tt)
select @tt

--inout
delimiter$
create procedure p9(inout age int)
begin
set age :=age+20;
end$
调用方法：
set @currentage=18
call p9(@currentage)
select @currentage

--case
delimiter$
create procedure p10()
begin
declare pos int default 0;
set pos:=floor(4*rand());
case pos
when 1 then select ‘happy‘;
when 2 then select ‘cry‘;
when 3 then select ‘angry‘;
else select ‘none‘;
end case;
end$

--repeat循环
delimiter$
create procedure p11()
begin
declare total int default 0;
declare i int default 0;
repeat
set i:=i+1;
set total :=total+i;
until i>=100 end repeat;
select total;
end$

[MySQL]存储过程

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