问题
used the following stored procedure to find reverse of a number , but it is showing error:use the right syntax to use near loop.
DELIMITER //
CREATE PROCEDURE ggrepeat1()
begin
declare num1 int;
declare num2 int;
declare rev int default 0;
set @num1:='&num1';
while num1>0
loop
set @num2:=num1 mod 10;
set @rev:=num2+(rev*10);
set @num1:=floor(num1/10);
end loop;
dbms_output.put_line('Reverse number is: '||rev);
end//
DELIMITER ;
回答1:
The while loop in mysql should be used in this like.
This is the first problem
while n>0 do
content..
end while
The second problem is
dbms_output.put_line('Reverse number is: '||rev);
In mysql you cannot use the above code.
Instead you can use this
Select 'The reverse of number is 'rev;
So your code would be
DELIMITER //
CREATE PROCEDURE ggrepeat1()
begin
declare num1 int;
declare num2 int;
declare rev int default 0;
set @num1:='&num1';
while num1>0 do
set @num2:=num1 mod 10;
set @rev:=num2+(rev*10);
set @num1:=floor(num1/10);
end while;
Select 'Reverse number is: 'rev;
end//
DELIMITER ;
回答2:
As noted in the comments, you can't use oracle syntax in mysql. Regardless, I think you're over-complicating things. A simpler approach would be to cast your number to a string, reverse it using built-in functions and cast it back to a number:
CREATE FUNCTION reverse_int(num INT)
RETURNS INT DETERMINISTIC
RETURN CAST(REVERSE(CAST(num AS CHAT)) AS INT);
来源：https://stackoverflow.com/questions/47853539/reverse-of-a-number-in-mysql