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 — Returns the number of rows in a result
설명
int pg_num_rows
( resource
$result
)pg_num_rows() will return the number of rows in a PostgreSQL result resource.
Note:
This function used to be called pg_numrows().
인수
-
result -
PostgreSQL query result resource, returned by pg_query(), pg_query_params() or pg_execute() (among others).
반환값
The number of rows in the result. On error, -1 is returned.
예제
Example #1 pg_num_rows() example
<?php
$result = pg_query($conn, "SELECT 1");
$rows = pg_num_rows($result);
echo $rows . " row(s) returned.\n";
?>
위 예제의 출력:
1 row(s) returned.
참고
- pg_num_fields() - Returns the number of fields in a result
- pg_affected_rows() - 영향 받은 레코드(튜플) 수를 반환
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.
