Question

I have a temp table and want to check in a where clause wether a certain id/string is contained in the temp table.

Select...
WHERE MyId  IN MyTempTable

I get a general error in MS SQL Management studio.

is the “In” operator not suited for temp tables?

Answer 1

Your syntax is wrong:

SELECT ...
  FROM MyTable
 WHERE MyID IN (SELECT MyID
                  FROM MyTempTable)

I don’t much like the IN operator, so I prefer this:

SELECT ...
  FROM MyTable
 WHERE EXISTS (SELECT *
                 FROM MyTempTable
                WHERE MyTable.MyID = MyID)

But it’s largely a matter of taste.