Actually what you are doing below is trying to stuff '' in a timestamp field. Keep in mind '' and NULL are not the same. '' is invalid for timestamp where as NULL is fine. Your example should be insert into T_Admin(name,key,regDate,isLock,realName) values('aaa','aaa',NULL,'1','aaa'); I think the bcp is trying to insert 'NULL' instead of NULL. According to the docs - looks like you can tell copy that http://www.postgresql.org/docs/techdocs.15 So my guess is you should do copy t_admin from "/home/postgres/data/admin.txt" USING DELIMITERS '\t' WITH NULL As 'NULL' Hope that helps, Regina -----Original Message----- From: pgsql-general-owner@xxxxxxxxxxxxxx [mailto:pgsql-general-owner@xxxxxxxxxxxxxx] On Behalf Of bookman bookman Sent: Monday, December 10, 2007 9:29 PM To: pgsql-general@xxxxxxxxxxxxxx Subject: How can I insert NULL into column with the type of timestamp? H i , I want to tansfer a database from sqlserver2005 to postgresql8.2.5.I use bcp to export a table named admin in sqlserver to a text file: --table T_admin id name key regDate isLock realName 1 rison 998877 2007-08-27 10:24:57 False admin 2 lijun 778899 NULL False NULL 3 guanliyuan 111111 2007-11-05 10:30:08 False myAdmin --admin.txt id name key regDate isLock realname 1 ris 998877 2007-08-27 10:24:57.000 0 admin 2 lij 778899 0 3 guanliyuan 111111 2007-11-05 10:30:08.813 0 myAdmin I created a table in postgresql,and I use "copy" to import datas create table T_Admin( adminID serial not null primary key, name varchar(30) null, key varchar(30) null, regDate timestamp null, isLock bool null, realName varchar(30) null ) copy admin from "/home/postgres/data/admin.txt" Then error occured: error:invalid input syntax for type timestamp:"" context:copy T_Admin ,line 2,column regDate:"" It seemed that the column REGDATE cannot accept a NULL.I tested it use: insert into T_Admin(name,key,regDate,isLock,realName) values('aaa','aaa','','1','aaa'); The same error occured. So it means that the column with type timestamp cannot accept a NULL ..Is there any way I can tansfer this table into postgre?How can i deal with NULL in this case? Thank you! ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq ----------------------------------------- The substance of this message, including any attachments, may be confidential, legally privileged and/or exempt from disclosure pursuant to Massachusetts law. It is intended solely for the addressee. If you received this in error, please contact the sender and delete the material from any computer. ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match