mysql ????????????????????????(1)?????? mysql?????????????????????????????????????????????????????????????????? ????????????????????????: Create procedure ProcedureName(Params[in,out]) Begin ???????? Declare?? attr attrType; ??????????proce

mysql??????????????????????????????????????????????????????????????????

????????????????????????:

Create procedure ProcedureName(Params[in,out])

Begin

???????? Declare?? attr attrType;

??????????procedure content;

End;

??

Example:

1. ????????????????????????

create procedure exampe1()
begin
?????????? declare l_student_count integer;
?????????? select count(*) into l_student_count from student;
??
?????????? ??select concat('there are totally ', l_student_count ,' students');
end;

??

2.??????????????????

???? drop procedure example1;

??

3.??????????????????????????????

create procedure example2(stu_id int)
begin
?????? declare stu_name varchar(30);
??
???????? select name into stu_name from student where student_id = stu_id;
???????? select stu_name;
end;

??

4.????????????????????????

create function example5() returns int
begin
???????? declare student_count int;
??
?????????? select count(*) into student_count from student;
?????????? return student_count;
end;

??

5.???????????????????????????

create trigger example6 before update on t for each row
begin
???? If New.percent < 0 then
???? ????set New.percent = 20;
???? Else
???? ????set New.percent = 100;
???? End If;
End;