mysql -- 逻辑语句

1.if语句

delimiter \
create procedure p1()
begin
    declare i int default 0;
    if i = 1 then
        select 1;
    elseif i = 2 then
        select 2;
    else
        select 3;
    end if;
end \
delimiter ;

2.循环

delimiter \
create procedure p1_while()
begin
 declare num int;
 set num =0;
 while num < 10 do
     select num;
     set num = num +1;
 end while;
end \
delimiter ;

delimiter \
create procedure p1_repeat()
begin
    declare i int;
    set i = 0;
    repeat
        select i;
        set i =i +1;
    until i>5 end repeat;
end \
delimiter ;

delimiter //
    declare i int default 0;
    loop_label: loop
           set i=i+1;
           if i<8 then
              iterate loop_label;
           end if;
           if i >=10 then
              leave loop_label;
           end if;
           select i;
   end loop loop_label;
delimiter ;