hi all

what is the difference between "IN" and "OR" command in MS SQL?

Both give the same results.

For simple scalar expressions, nothing, though the IN clause is usually less typing. A WHERE clause like:

WHERE somecolumn = 1 OR somecolumn = 2

will result in a query plan that is identical to:

WHERE somecolumn IN (1,2)

Of course, the IN clause is really a 'set contains' operator, so you can construct expressions that are not really feasible with an OR operator, e.g:

WHERE somecolumn IN (SELECT acolumn FROM sometable)

__________________
-- Jeff

And the biggest difference, of course, is that IN can only be used with one field/column/test value.

OR is more flexible. IN is much more efficient in those situations where it can be used.