mysqli_fetch

PHP 手册
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Description

Procedural style:

array mysqli_fetch_lengths ( mysqli_result result )

Object oriented style (property):

class mysqli_result {

array lengths

}

The mysqli_fetch_lengths() function returns an array containing the lengths of every column of the current row within the result set represented by the result parameter. If successful, a numerically indexed array representing the lengths of each column is returned or FALSE on failure.

返回值

An array of integers representing the size of each column (not including any terminating null characters). FALSE if an error occurred.

mysqli_fetch_lengths() is valid only for the current row of the result set. It returns FALSE if you call it before calling mysqli_fetch_row/array/object or after retrieving all rows in the result.

范例

例子 1. Object oriented style


<?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();
?>

例子 2. Procedural style


<?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);
?>

上例将输出：

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

后退	起点	前进
mysqli_fetch_fields	上一级	mysqli_fetch_object