SQL Constants

The following constants can be used in queries:

Special Constant	Meaning
Now	Current date and time. This constant must be specified in quotes. Note: This constant only works when used within the SQL date() function. Current date (as ANSI date type)
Null	Indicates a missing or unknown value in a table.
Today	Current date. This constant must be specified in quotes. Note: This constant only works when used within the SQL date() function.
current_date	Current date (as ANSI date type)
current_time	Current time
current_timestamp	Current date and time
local_time	Current time without time zone
local_timestamp	Current date and time without time zone
User	Effective user of the session (the Ingres user identifier, not the operating system user identifier).
current_user	Same as user.
system_user	Operating system user identifier of the user who started the session.
initial_user	Ingres user identifier in effect at the start of the session.
session_user	Same as user.

These constants can be used in queries and expressions. They can be used any number of times in a query, but the value is only materialized once per query execution. So a constant such as CURRENT_TIME can be referenced in an INSERT statement that inserts many rows, or an UPDATE statement that alters many rows, and the same time value will be used for each.

For example:

select date('now');

insert into sales_order
(item_number, clerk, billing_date)
values ('123', user, date('today')+date('7 days'));

update employee set e_sal = e_sal * 1.05, e_udp_time = CURRENT_TIMESTAMP where e_stat = 'x';

To specify the effective user at the start of a session, use the Ingres -u flag (for operating system commands) or the identified by clause of the SQL connect statement.