Question

When inserting values into TARGET_TABLE with below INSERT..SELECT statement, the column default for the column lastupdate seems to be prioritized over the value resulting from the SELECT statement.

Even though there is always a value for this column in the SOURCE_TABLE.

Example:

SOURCE_TABLE contains lastupdate = 16.08.12 15:41:44

After executing the statement, lastupdate in TARGET_TABLE gets set to SYSDATE, e.g. 16.08.12 15:49:14:

INSERT INTO TARGET_TABLE (A, B, C, D, LASTUPDATE, F)
        SELECT A, B, C, D, LASTUPDATE, F
            FROM SOURCE_TABLE
            WHERE B = 'some_value';


CREATE TABLE TARGET_TABLE
(
ID NUMBER NOT NULL,
A VARCHAR2(255 CHAR) NOT NULL,
B VARCHAR2(255 CHAR) NOT NULL,
C CLOB NOT NULL,
D VARCHAR2(255 CHAR),
LASTUPDATE DATE DEFAULT SYSDATE,
E DATE DEFAULT SYSDATE
)

Oracle version: Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 – 64bit Production

I would like the value to be copied from SOURCE_TABLE to TARGET_TABLE and not to be set to SYSDATE.

What am I missing here? Thank you.

Answer 1

Can you copy and paste from a SQL*Plus session showing this behavior? It doesn’t reproduce on my 11.2 database and it’s not something that I’ve ever personally seen happen.

SQL> CREATE TABLE TARGET_TABLE
  2  (
  3  ID NUMBER NOT NULL,
  4  A VARCHAR2(255 CHAR) NOT NULL,
  5  B VARCHAR2(255 CHAR) NOT NULL,
  6  C CLOB NOT NULL,
  7  D VARCHAR2(255 CHAR),
  8  LASTUPDATE DATE DEFAULT SYSDATE,
  9  E DATE DEFAULT SYSDATE
 10  );

Table created.

SQL> ed
Wrote file afiedt.buf

  1  CREATE TABLE SOURCE_TABLE
  2  (
  3  ID NUMBER NOT NULL,
  4  A VARCHAR2(255 CHAR) NOT NULL,
  5  B VARCHAR2(255 CHAR) NOT NULL,
  6  C CLOB NOT NULL,
  7  D VARCHAR2(255 CHAR),
  8  LASTUPDATE DATE DEFAULT SYSDATE,
  9  E DATE DEFAULT SYSDATE
 10* )
SQL> /

Table created.

I had to change your INSERT into SOURCE_TABLE to specify the column E rather than F since the CREATE TABLE statement only had a column E.

SQL> insert into source_table( id, a, b, c,d, lastupdate, e )
  2    values( 1, 'A', 'some_value', empty_clob(), 'D', date '2012-01-01', sysdate );

1 row created.

I also had to change your INSERT into TARGET_TABLE to add the ID column since that has a NOT NULL constraint. I’m assuming that in your actual example this is probably getting populated by a trigger on TARGET_TABLE that is selecting the data from a sequence. Is it possible that this trigger (or some other trigger) is setting the LASTUPDATE value as well?

SQL> ed
Wrote file afiedt.buf

  1  INSERT INTO TARGET_TABLE (ID, A, B, C, D, LASTUPDATE, E)
  2          SELECT ID, A, B, C, D, LASTUPDATE, E
  3              FROM SOURCE_TABLE
  4*             WHERE B = 'some_value'
SQL> /

1 row created.

SQL> select id, lastupdate from target_table;

        ID LASTUPDAT
---------- ---------
         1 01-JAN-12