Setting Default TIMESTAMP in SQL Column

Question

I am creating a Table and I have a column that is TIMESTAMP.

I want to set a default value to it. How can I do that ?

For Example:

I have a USER_LAST_SEEN table, and I have two columns:

1) username 2) logout date

and I want to be able to tell if a user has never been logged out yet, by setting a default timestamp I can then look for. How do I do that ?

CREATE TABLE LAST_SEEN_TABLE (USERNAME STRING, LOGOUT_DATE TIMESTAMP [What am I missing here?])

Edit: Saving NULL is not a good solution, because of the scenario that a user already exists when I create the table. Showing "Never logged in", which is shown when a user DOES have NULL, is wrong in this case. I need a way to have ANOTHER indication that user DID log in before in order to show "N/A"

Why don't just leave the logout date as NULL if user never logs out ? — rcs
– rcs, Commented Aug 21, 2018 at 6:24
Which DBMS product are you using? "SQL" is just a query language, not the name of a specific database product. Please add a tag for the database product you are using postgresql, oracle, sql-server, db2, ... — user330315
– user330315, Commented Aug 21, 2018 at 6:27
Just add default constraint as current_timestamp to your column . — IShubh
– IShubh, Commented Aug 21, 2018 at 6:29
@rcs the "NULL" is in fact used for something else in this context. That's why I don't use it and I'm looking for another solution — Ofri
– Ofri, Commented Aug 21, 2018 at 6:46

rcs · Accepted Answer · 2018-08-21 07:14:40Z

2

If you cannot use NULL, you can use a specific date, for example '1900-01-01'

CREATE TABLE LAST_SEEN_TABLE 
(
    USERNAME varchar(100), 
    LOGOUT_DATE TIMESTAMP default '1900-01-01 00:00:00'
);

answered Aug 21, 2018 at 7:14

rcs

7,31713 gold badges61 silver badges88 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Ofri Over a year ago

Thank you, this is what I want to know how to do !

Collectives™ on Stack Overflow

Setting Default TIMESTAMP in SQL Column

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related