I've figured it out, that is using 'null as <null string>' with the COPY
command.
Bing
> The table is like this:
>
> ========
> maxware=# \d test;
> Table "public.test"
> Column | Type | Modifiers
> --------+-----------------------------+-----------
> a | timestamp without time zone |
> b | integer |
> =========
>
> The following insert command works fine:
>
> maxware=# insert into test (a,b) values (null,'1');
>
> But importing from an input data file does not seem to work as shown
> below:
>
> =========
> maxware=# copy tbl_spcase from '/home/bdu/test/input.data' delimiter as
> '|';
> ERROR: invalid input syntax for integer: "null"
> CONTEXT: COPY tbl_spcase, line 1, column col_id_spcase: "null"
> ==========
>
> The input.data file just has one line. But no matter what I did, neither
> of the following input format worked.
>
> 1. null|1
> 2. |1
> 3. ''|1
>
> How should I represent blank value for the field that's of timestamp type?
>
> Thanks in advance for any help,
>
> Bing
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: you can get off all lists at once with the unregister command
> (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
>