mysqli_result::$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($link);
?>上面的例子会输出：
Field 1 has Length 3
Field 2 has Length 5
Field 3 has Length 13
Field 4 has Length 9
Field 5 has Length 6
Field 6 has Length 1
Field 7 has Length 6
Field 8 has Length 4
Field 9 has Length 6
Field 10 has Length 6
Field 11 has Length 5
Field 12 has Length 44
Field 13 has Length 7
Field 14 has Length 3
Field 15 has Length 2mysqli_result::$num_rows →
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