php中mysql_affected_rows()更新记录返回0_php中mysql_affected_rows()返回-1帶來的“陷阱” | 學步園...

$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');

if (!$link) {

die('Could not connect: ' . mysql_error());

}

mysql_select_db('mydb');

/* 本例返回被刪除記錄的準確數目 */

mysql_query('DELETE FROM mytable WHERE id < 10');

printf("Records deleted: %d/n", mysql_affected_rows());

/* 對於非真值的 WHERE 子句，應返回 0 */

mysql_query('DELETE FROM mytable WHERE 0');

printf("Records deleted: %d/n", mysql_affected_rows());

/*一個插入失敗的SQL語句，因為返回值為-1，會輸出OK*/

mysql_query("insert into tableA(id)values('XXX')");

$affected_rows = mysql_affected_rows();

/*問題出在if這裡，執行成功則返回受影響的行的數目，如果最近一次查詢失敗的話，函數返回 -1。*/

if($affected_rows)

echo 'OK';

else

echo 'ERROR';