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 — Возвращает количество строк в выборке
Описание
pg_num_rows(resource
$result): intpg_num_rows() возвращает количество строк в результате запроса PostgreSQL.
Замечание:
Ранее функция называлась pg_numrows().
Список параметров
-
result -
Результат запроса PostgreSQL, возвращаемый функциями pg_query(), pg_query_params() или pg_execute() (и прочими).
Возвращаемые значения
Количество строк в выборке. В случае ошибки возвращает -1.
Примеры
Пример #1 Пример использования pg_num_rows()
<?php
$result = pg_query($conn, "SELECT 1");
$rows = pg_num_rows($result);
echo "Возвращено строк: " . $rows . ".\n";
?>
Результат выполнения данного примера:
Возвращено строк: 1.
Смотрите также
- pg_num_fields() - Возвращает количество полей в выборке
- pg_affected_rows() - Возвращает количество затронутых запросом записей (кортежей)
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.
