mysqli_result::$num_rows()
(PHP 5, PHP 7)
Gets the number of rows in a result
说明
面向对象风格
int $mysqli_result->num_rows;
过程化风格
mysqli_num_rows(mysqli_result$result): int
Returns the number of rows in the result set.
The behaviour of mysqli_num_rows() depends on whether buffered or unbuffered result sets are being used. For unbuffered result sets,mysqli_num_rows() will not return the correct number of rows until all the rows in the result have been retrieved.
参数
- $result
仅以过程化样式:由mysqli_query(),mysqli_store_result()或mysqli_use_result()返回的结果集标识。
返回值
Returns number of rows in the result set.
Note:If the number of rows is greater than
PHP_INT_MAX
, the number will be returned as a string.
范例
Example #1 面向对象风格
<?php $mysqli = new mysqli("localhost", "my_user", "my_password", "world"); /* check connection */ if (mysqli_connect_errno()) { printf("Connect failed: %s\n", mysqli_connect_error()); exit(); } if ($result = $mysqli->query("SELECT Code, Name FROM Country ORDER BY Name")) { /* determine number of rows result set */ $row_cnt = $result->num_rows; printf("Result set has %d rows.\n", $row_cnt); /* close result set */ $result->close(); } /* close connection */ $mysqli->close(); ?>
Example #2 过程化风格
<?php $link = mysqli_connect("localhost", "my_user", "my_password", "world"); /* check connection */ if (mysqli_connect_errno()) { printf("Connect failed: %s\n", mysqli_connect_error()); exit(); } if ($result = mysqli_query($link, "SELECT Code, Name FROM Country ORDER BY Name")) { /* determine number of rows result set */ $row_cnt = mysqli_num_rows($result); printf("Result set has %d rows.\n", $row_cnt); /* close result set */ mysqli_free_result($result); } /* close connection */ mysqli_close($link); ?>
以上例程会输出:
Result set has 239 rows.
参见
- mysqli_affected_rows() Gets the number of affected rows in a previous MySQL operation
- mysqli_store_result() 转移上一次查询返回的结果集
- mysqli_use_result() Initiate a result set retrieval
- mysqli_query() 对数据库执行一次查询
If you have problems making work this num_rows, you have to declare ->store_result() first. <?php $mysqli = new mysqli("localhost","root", "", "tables"); $query = $mysqli->prepare("SELECT * FROM table1"); $query->execute(); $query->store_result(); $rows = $query->num_rows; echo $rows; // Return 4 for example ?>
The method signature should be: mixed mysqli_num_rows (mysqli_result $result) "If the number of rows is greater than PHP_INT_MAX, the number will be returned as a string."
This function doesn't work with LIMIT used jointly with SQL_CALC_FOUND_ROWS. If you want to obtain the total rows found you must do it manually, example: <?php public function errorList(int $limit=25,int $offset=0){ $errorList = array(); $result = $this->con->query("SELECT SQL_CALC_FOUND_ROWS id, erreur FROM Erreurs ORDER BY id DESC LIMIT $limit OFFSET $offset"); while($row = $result->fetch_assoc()){ $errorList[] = new Erreur($row); } $result->free(); // $foundRows = $result->num_rows; // 25 $foundRows = $this->con->query("SELECT FOUND_ROWS() as foundRows"); $this->foundRows = $foundRows->fetch_assoc(); // 178 return $errorList; } ?>
in php 5.3.8 had unexpected troubles when checking for mysqli_result::$num_rows If the result of the query is empty then var_dump of the result will be like this: class mysqli_result#5 (5) { public $current_field => NULL public $field_count => NULL public $lengths => NULL public $num_rows => NULL public $type => NULL } but var_dump($result->num_rows) will give integer-typed zero instead of NULL: int(0)
// Create Database Connection .. $conn = new mysqli("localhost", "root", "", "my_db"); // run a query on a table from your DB. $sql_rec = $conn->query("select count(msisdn) from my_colum where id = '$id'"); // Take out the Where Clause if not Needed. if($sql_rec == true) { echo " The Total Number of MSISDNs are " . $sql_rec->num_rows; } else { echo "Something Bad has happened, We have informed the village Elders.". $conn->connect_error(); } $conn->close();