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pg_num_rows — Gibt die Anzahl der Zeilen in einem Abfrageergebnis zurück
pg_num_rows() gibt die Anzahl der Zeilen in einem PostgreSQL Abfrageergebnis zurück.
Hinweis:
Diese Funktion ersetzt die Funktion pg_numrows().
PostgreSQL Ergebniskennung für eine Abfrage, die (unter anderem) von pg_query(), pg_query_params() oder pg_execute() zurückgegeben wurde.
Die Anzahl der Zeilen in einem Abfrageergebnis. Tritt ein Fehler auf, wird -1 zurückgegeben.
Beispiel #1 pg_num_rows() Beispiel
<?php
$result = pg_query($conn, "SELECT 1");
$rows = pg_num_rows($result);
echo $rows . " Zeile(n) gefunden.\n";
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
1 Zeile(n) gefunden.
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
?>
About preceding note, you shouldn't use pg_num_rows() for this.
You should have instead a look at pg_affected_rows().
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.
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