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)
pg_num_rows — Zwraca ilość wierszy w wyniku
Opis
pg_num_rows
( resource
$result
) : intpg_num_rows() zwróci ilość wierszy w zasobie wyniku PostgreSQL.
Informacja:
Ta funkcja nazywała się kiedyś pg_numrows().
Parametry
-
result -
Zasób wyniku zapytania PostgreSQL zwrócony przez pg_query(), pg_query_params() lub pg_execute() (między innymi).
Zwracane wartości
Ilość wierszy w wyniku. W razie błędu zwracane jest -1.
Przykłady
Przykład #1 Przykład użycia pg_num_rows()
<?php
$result = pg_query($conn, "SELECT 1");
$rows = pg_num_rows($result);
echo "Zwróconych wierszy: " . $rows . "\n";
?>
Powyższy przykład wyświetli:
Zwróconych wierszy: 1
Zobacz też:
- pg_num_fields() - Zwraca ilość pól w wyniku
- pg_affected_rows() - Zwraca liczbę zmodyfikowanych wierszy
add a note
User Contributed Notes 3 notes
strata_ranger at hotmail dot com ¶
14 years ago
ElDiablo ¶
15 years ago
About preceding note, you shouldn't use pg_num_rows() for this.
You should have instead a look at pg_affected_rows().
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.
