根据现有行将行插入SQL表

Question

I need to add a new row to a table in Oracle. The problem is that the table has 50 columns and I really don't want to write them all out for an INSERT statement. I tried to do a SELECT INTO statement to duplicate the row and then change the fields I care about individually, but this results in a UNIQUE violation on the primary key. So what I really want to do is declare a variable that holds one row without naming all the columns, change the primary key field, and then insert that variable. How do?

Answer 1

You can use %ROWTYPE in an anonymous PL/SQL block to declare a record representing a row from a table and then select a row into that record and change the primary key and insert the updated record. You can even re-use it for multiple inserts:

DECLARE
  rec SOME_TABLE%ROWTYPE;
BEGIN
  SELECT *
  INTO   rec
  FROM   SOME_TABLE
  WHERE  A = 1; -- Primary Key

  rec.A := 2; -- Change the primary key value.
  INSERT INTO SOME_TABLE VALUES rec;

  rec.A := 3; -- Change the primary key again.
  INSERT INTO SOME_TABLE VALUES rec;

  FOR i IN 4 .. 9 LOOP
    rec.A := i; -- Change it repeatedly...
    INSERT INTO SOME_TABLE VALUES rec;
  END LOOP;

  FOR i IN 1 .. 3 LOOP
    rec.A := SOME_SEQUENCE.NEXTVAL; -- Or you can manage the primary key's value using a sequence.
    INSERT INTO SOME_TABLE VALUES rec;
  END LOOP;
END;
/

SQLFIDDLE

Answer 2

I have often wanted to do something similar to this, but it's just not possible in any SQL variant I know of. You cannot ask for only some of the columns in a table without explicitly naming them (or perhaps defining a view on them in advance).

The only shortcut I can suggest is to dump the list of column names into a convenient location and then just copy it into an insert statement, changing only the value you need:

insert into foo (select 'newC1' as c1, c2, c3, c4, ..., c50 from foo where bar='baz');

::edit:: In fact, I do this so often that I wrote a Python script to help me. I tell it what table I'm editing, some where clause that matches exactly 1 row, the list of column(s) I want to change, and the list of new value(s) I want in those columns. Then it does the rest.