Problems With Joins, It Freezes

Hi all

I have a master table, with ID Column int, and Description column Varchar

And another details table, with MasterID Int, and Detail id INT

If i use this query:
SELECT * FROM table1 a INNER JOIN table2 b ON a.id_col=b.id_col
Never returns data, and get freeze, and i have to kill process on Managment

But if i use this:
SELECT * FROM table1 a INNER JOIN table2 b ON a.id_col=b.id_col+0

It returns data i Want, is this a Bug? Or i have an error?
The 2 columns is the same data.

But if I run this,
SELECT * FROM table1 a INNER JOIN table2 b ON a.id_col+0=b.id_col
Nothing happens,

What could it be?