(PHP 5, PHP 7)
mysqli_result::field_seek -- mysqli_field_seek — Set result pointer to a specified field offset
面向对象风格
$fieldnr
   )过程化风格
Sets the field cursor to the given offset. The next call to mysqli_fetch_field() will retrieve the field definition of the column associated with that offset.
Note:
To seek to the beginning of a row, pass an offset value of zero.
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。
fieldnrThe field number. This value must be in the range from 0 to number of fields - 1.
   成功时返回 TRUE, 或者在失败时返回 FALSE。
  
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();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5";
if ($result = $mysqli->query($query)) {
    /* Get field information for 2nd column */
    $result->field_seek(1);
    $finfo = $result->fetch_field();
    printf("Name:     %s\n", $finfo->name);
    printf("Table:    %s\n", $finfo->table);
    printf("max. Len: %d\n", $finfo->max_length);
    printf("Flags:    %d\n", $finfo->flags);
    printf("Type:     %d\n\n", $finfo->type);
    $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();
}
$query = "SELECT Name, SurfaceArea from Country ORDER BY Code LIMIT 5";
if ($result = mysqli_query($link, $query)) {
    /* Get field information for 2nd column */
    mysqli_field_seek($result, 1);
    $finfo = mysqli_fetch_field($result);
    printf("Name:     %s\n", $finfo->name);
    printf("Table:    %s\n", $finfo->table);
    printf("max. Len: %d\n", $finfo->max_length);
    printf("Flags:    %d\n", $finfo->flags);
    printf("Type:     %d\n\n", $finfo->type);
    mysqli_free_result($result);
}
/* close connection */
mysqli_close($link);
?>
以上例程会输出:
Name: SurfaceArea Table: Country max. Len: 10 Flags: 32769 Type: 4