Define a Column for Which the Value Must Be Computed

IDENTITY column values are generated by SAP ASE. New columns that are based on IDENTITY columns, and for which the values must be computed rather than generated, cannot inherit the IDENTITY property.

If a table’s select statement includes an IDENTITY column as part of an expression, the resulting column value must be computed. The new column is created as NULL if any column in the expression allows a NULL value. Otherwise, it is NOT NULL.

In the following example, the new_id column, which is computed by adding 1000 to the value of record_id, is created NOT NULL:

select new_id = record_id + 1000, stor_name
into new_stores
from stores_cal

Column values are also computed if the select statement contains a group by clause or aggregate function. If the IDENTITY column is the argument of the aggregate function, the resulting column is created NULL. Otherwise, it is NOT NULL.