mysqli_result::$lengths
mysqli_result::$lengths
mysqli_fetch_lengths
(PHP 5, PHP 7)
mysqli_result :: $ lengths -- mysqli_fetch_lengths — 返回结果集中当前行的列的长度
描述
面向对象的风格
array $mysqli_result->lengths;
程序风格
array mysqli_fetch_lengths ( mysqli_result $result )
所述mysqli_fetch_lengths（）函数返回一个包含结果集内的当前行的每一列的长度的阵列。
参数
`result`
仅过程风格：由mysqli_query（），mysqli_store_result（）或mysqli_use_result（）返回的结果集标识符。
返回值
表示每列大小的整数数组（不包括任何终止的空字符）。如果发生错误返回FALSE。
mysqli_fetch_lengths（）仅对结果集的当前行有效。FALSE如果在调用mysqli_fetch_row / array / object之前或在检索结果中的所有行之后调用它，它将返回。
例子
Example＃1面向对象的风格
<?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(
}
$query = "SELECT * from Country ORDER BY Code LIMIT 1";
if ($result = $mysqli->query($query)) {
$row = $result->fetch_row(
/* display column lengths */
foreach ($result->lengths as $i => $val) {
printf("Field %2d has Length %2d\n", $i+1, $val
}
$result->close(
}
/* close connection */
$mysqli->close(
?>
示例＃2程序风格
<?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(
}
$query = "SELECT * from Country ORDER BY Code LIMIT 1";
if ($result = mysqli_query($link, $query)) {
$row = mysqli_fetch_row($result
/* display column lengths */
foreach (mysqli_fetch_lengths($result) as $i => $val) {
printf("Field %2d has Length %2d\n", $i+1, $val
}
mysqli_free_result($result
}
/* close connection */
mysqli_close($link
?>
上面的例子会输出：
Field 1 has Length 3
Field 2 has Length 5
Field 3 has Length 13
Field 4 has Length 9
Field 5 has Length 6
Field 6 has Length 1
Field 7 has Length 6
Field 8 has Length 4
Field 9 has Length 6
Field 10 has Length 6
Field 11 has Length 5
Field 12 has Length 44
Field 13 has Length 7
Field 14 has Length 3
Field 15 has Length 2
mysqli_result::$num_rows →
