Hi, Is It possible to add new column in table after checking whether column already exists or not?Ap

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  [Deleted User]

  January 2014

  It wasn't clear if you were trying to do this manually or programmatically. There's no function to test for exists, you'd have to use "\d tablename" or parse the results of "select * from tablename limit 0" to check for the column. In recent versions you can add a column to a table. See alter table in the sql guide for more details. Here's an example.
  
  => \d testaddcol
                                        List of Fields by Tables
   Schema |   Table    | Column |    Type     | Size | Default | Not Null | Primary Key | Foreign Key
  --------+------------+--------+-------------+------+---------+----------+-------------+-------------
   public | testaddcol | c1     | int         |    8 |         | f        | f           |
   public | testaddcol | c2     | varchar(20) |   20 |         | f        | f           |
  (2 rows)
  
  => select * from testaddcol;
   c1 | c2
  ----+-----
    2 | two
    1 | one
  (2 rows)
  
  => alter table testaddcol add column c3 timestamp default '2014-01-01';
  ALTER TABLE
  ndw=> \d testaddcol
                                                    List of Fields by Tables
   Schema |   Table    | Column |    Type     | Size |             Default              | Not Null | Primary Key | Foreign Key
  --------+------------+--------+-------------+------+----------------------------------+----------+-------------+-------------
   public | testaddcol | c1     | int         |    8 |                                  | f        | f           |
   public | testaddcol | c2     | varchar(20) |   20 |                                  | f        | f           |
   public | testaddcol | c3     | timestamp   |    8 | '2014-01-01 00:00:00'::timestamp | f        | f           |
  (3 rows)
  
  => select * from testaddcol;
   c1 | c2  |         c3
  ----+-----+---------------------
    2 | two | 2014-01-01 00:00:00
    1 | one | 2014-01-01 00:00:00
  (2 rows)
  
  I hope it helps.
  

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