Adding columns with SQL

[Alderaan]

I have a table called "Table", I want SQL to add a column "C1" (INT(11)) if "Table" does not contains already "C1". IF "Table" already contains "C1", then do nothing.

How can I do that under SQL?

Thanks

[NoMercy]

ALTER TABLE 'Table' ADD C1 INT(11);

I can't think of any nice way of testing if the column exists, but if it does this statement will in theory just generate an error.