[#1] spamuser at test dot com [2011-03-16 13:14:45]

pg_result_error does NOT work with prepared statements.

[#2] axon dot wp at wp dot pl [2006-03-02 16:20:07]

You can  use pg_set_error_verbosity() to retrieve SQLSTATUS from pg_last_error().

[#3] [2004-03-15 16:12:16]

Because pg_query() returns FALSE if the query fails, you must must use pg_send_query() and pg_get_result() to get the result handle.

PostgreSQL 7.4 introduced a new function called PQresultErrorField() that can be used to get SQLSTATE code from a query, which is far more useful than the error string returned from pg_result_error().
http://www.postgresql.org/docs/7.4/static/libpq-exec.html
http://www.postgresql.org/docs/7.4/static/errcodes-appendix.html

Here's a patch that adds the pg_result_error_field() function to PHP:
http://collapsed.net/patches/php-4.3.5RC3-pg_result_error_field.diff
(To apply the patch cd into your php-4.3.5RC directory and type: patch -p1 </path/to/php-4.3.5RC3-pg_result_error_field.diff)

Example code:
<?php
  if(!($db = pg_connect("user=foo password=bar dbname=foobar")))
    die("pg_connect");

  if(!pg_send_query($db, "SELECT foo FROM bar"))
    die("pg_send_query");

  if(!($result = pg_get_result($db)))
    die("pg_get_result");

  echo(pg_result_error($result) . "<br />\n");

  
  if(function_exists("pg_result_error_field"))
  {
    $fieldcode = array(
      "PGSQL_DIAG_SEVERITY",        "PGSQL_DIAG_SQLSTATE",
      "PGSQL_DIAG_MESSAGE_PRIMARY", "PGSQL_DIAG_MESSAGE_DETAIL",
      "PGSQL_DIAG_MESSAGE_HINT",    "PGSQL_DIAG_STATEMENT_POSITION",
      "PGSQL_DIAG_CONTEXT",         "PGSQL_DIAG_SOURCE_FILE",
      "PGSQL_DIAG_SOURCE_LINE",     "PGSQL_DIAG_SOURCE_FUNCTION");

    foreach($fieldcode as $fcode)
    {
      printf("%s: %s<br />\n",
        $fcode,
        pg_result_error_field($result, constant($fcode)));
    }

    pg_free_result($result);
  }
?>

<?php pg_result_error_field($result, PGSQL_DIAG_SQLSTATE); ?>
Returns the SQLSTATE code.