mysql存储过程目前只支持存储过程，存储函数，触发器

存储过程基本结构:

Create procedure ProcedureName(Params[in,out])

Begin

???? Declare? attr attrType;

?????procedure content;

End;

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Example:

1. 创建基本存储过程

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;

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2.删除存储过程

?? drop procedure example1;

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3.创建带入参的存储过程

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;

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4.创建函数基本结构

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

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5.创建触发器基本结构

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;