I need to know that original number of rows that WOULD have been returned
by a SELECT statement if the LIMIT / OFFSET where not present in the statement.
Is there a way to get this data from PG ?

   ... ;

----> returns 100,000 rows


   LIMIT x
   OFFSET y;

----> returns at most x rows

In order to build a list pager on a web site, I want to select 'pages' of a
result set at a time. However, I need to know the original select result set
size because I still have to draw the 'page numbers' to display what pages are

I've done this TWO ways in the past:

   1) TWO queries.  The first query will perform a SELECT COUNT(*) ...; and
   the second query performs the actualy SELECT ... LIMIT x OFFSET y;

2) Using PHP row seek and only selecting the number of rows I need.

Here is an example of method number 2 in PHP:

   function query_assoc_paged ($sql, $limit=0, $offset=0) {
       $this->num_rows = false;

       // open a result set for this query...
       $result = $this->query($sql);
       if (! $result) return (false);

       // save the number of rows we are working with
       $this->num_rows = @pg_num_rows($result);

       // moves the internal row pointer of the result to point to our
       // desired offset. The next call to pg_fetch_assoc() would return
       // that row.
       if (! empty($offset)) {
           if (! @pg_result_seek($result, $offset)) {
               return (array());

// gather the results together in an array of arrays...
$data = array();
while (($row = pg_fetch_assoc($result)) !== false) {
$data[] = $row;
// After reading N rows from this result set, free our memory
// and return the rows we fetched...
if (! empty($limit) && count($data) >= $limit) {
return ($data);



In this approach, I am 'emulating' the LIMIT / OFFSET features in PostgreSQL
by just seeking forward in the result set (offset) and only fetching the
number of rows that match my needs (LIMIT).

QUESTION: Is this the best way to do this, or is there a more efficient way
to get at the data I want?  Is there a variable set in PG that tells me the
original number of rows in the query?  Something like:

   LIMIT x
   OFFSET y;

Or can I run another select right afterwards...like:

   SELECT ...
   LIMIT x
   OFFSET y;

SELECT unfiltered_size_of_last_query();

Any thoughts?  Sure, the PHP function I'm using above 'works', but is it
the most efficient?  I hope I'm not actually pulling all 100,000 records
across the wire when I only intend to show 10 at a time.  See what I'm
getting at?



D. Dante Lorenso

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