IDENTITY column values are generated by Adaptive Server. New columns that are based on IDENTITY columns, but whose 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.
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