Sybase IQ: How to alter the size/type of an existing column

Sybase IQ does not support alter table with change column data type functionality. I don’t know if this is the case with the new version (15). If you are using a version prior 15 you must do the following:

• First create a table similar to the source but with updated the column to the new data type.

                create table tmp_old_table_name 

                /* unchanged column definitions here */ 

                , old_column  new_type 

                ;

• Then we must copy the contents of the original table to the newly created one.

                insert tmp_old_table
                (/* column list here */)
                select /* column list here */
                from old_table
                ;

• Now that the data's there, create any other indexes you want.

                create index extra_index /* blah blah */
                ;

• Drop or rename old table to backup

                drop table old_table
                ;

• Rename new table to old table name

                sp_rename tmp_old_table, old_table
                ;