As mentioned, if you are performing an INSERT/UPDATE or DELETE query and want to know the # of rows affected, you should use pg_affected_rows() instead of pg_num_rows().
However, you can also exploit postgres's RETURNING clause in your query to auto-select columns from the affected rows. This has the advantage of being able to tell not only how many rows a query affects, but exactly which rows those were, especially if you return a primary-key column.
For example:
<?php
// Example query. Let's say that this updates five rows in the source table.
$res = pg_query("Update foo set bar = 'new data' where foo.bar = 'old data' ");
pg_num_rows($res); // 0
pg_affected_rows($res); // 5
pg_fetch_all($res); // FALSE
// Same query, with a RETURNING clause.
$res = pg_query("Update foo set bar = 'new data' where foo.bar = 'old data' RETURNING foo.pkey");
pg_num_rows($res); // 5
pg_affected_rows($res); // 5
pg_fetch_all($res); // Multidimensional array corresponding to our affected rows & returned columns
?>
pg_num_rows
(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
pg_num_rows — Restituiscein numero di tuple
Descrizione
pg_num_rows() restituisce il numero di tuple (righe) in un
risultato PostgreSQL.
risultato รจ una risorsa risultato ottenuta
attraverso pg_query(). Restituisce -1 in
caso di errore.
Nota:
Utilizzare pg_affected_rows() per ottenere il numero di righe modificate da query INSERT, UPDATE and DELETE.
Nota:
Questa funzione si chiamava
pg_numrows().
Vedere anche pg_num_fields() e pg_affected_rows().
add a note
User Contributed Notes 3 notes
strata_ranger at hotmail dot com ¶
15 years ago
francisco at natserv dot com ¶
16 years ago
Not sure why this documentation doesn't have the following note:
Note: Use pg_affected_rows() to get number of rows affected by INSERT, UPDATE and DELETE query.
Found on other resources. Adding here in case someone else is looking for the info.
