fbsql_num_rows()

(PHP 4 >= 4.0.6, PHP 5, PHP 7)

Get number of rows in result

说明

fbsql_num_rows(resource $result): int

Gets the number of rows in the given$resultset.

This function is only valid for SELECT statements. To retrieve the number of rows returned from a INSERT, UPDATE or DELETE query, use fbsql_affected_rows().

参数

$result: 由fbsql_query()或fbsql_db_query()返回的结果标识符。

返回值

Returns the number of rows returned by the last SELECT statement.

范例

Example #1 fbsql_num_rows() example

<?php
$link = fbsql_connect("localhost", "username", "password");
fbsql_select_db("database", $link);
$result = fbsql_query("SELECT * FROM table1;", $link);
$num_rows = fbsql_num_rows($result);
echo "$num_rows Rows\n";
?>

参见

fbsql_affected_rows()Get number of affected rows in previous FrontBase operation
fbsql_connect()Open a connection to a FrontBase Server
fbsql_select_db()Select a FrontBase database
fbsql_query()Send a FrontBase query

Note that this function will not always return the actual size of a result set. For example, if you are doing a two-table join along the lines of "SELECT * FROM T1,T2 where T1.x=T2.x" you will get a result of -1. This is due to the 'lazy execution' model in FrontBase whereby result rows are only returned as you request them. If you absolutely have to have the number of rows in advance then you will have to use COUNT(*) first. Most of the time you do not need to know the exact number of rows; it is good enough to know if the size of the result set is non-zero.
David Gillies
San Jose
Costa Rica