Basically, does anyone know how to insert the thousandth operator using SQL?
What do you mean with "thousandth operator"? If it is thousandth expression in IN condition list, then it is fine - IN condition accepts at most thousand expressions. If you still intend to put there more expressions, you might use multiple IN conditions, e.g.
WHERE <column> IN (1, 2, ..., 1000)
OR <column> IN (1001, 1002, ...)
But, I would not expect good performance from this kind of query.
It would be much better to create a table and INSERT all expression values there, and then simply use
WHERE <column> IN (SELECT <new_column> FROM <new_table>)
What is "thousandth operator"? How does it look like? What does it do?
Is this what you are looking for ("separator" instead of "operator")? If so, I believe that there's yet another option: instead of "hardcoding" that separator (to, for example, a comma (,) sign), use G (for "group") and D (for "decimal") separators: