Note that for some reason the length of fields is 3 times the actual value if you are using UTF8 encoding.. So a varchar(10) field returns 30 here. This renders this function almost useless.
mysql_field_len
(PHP 4, PHP 5)
mysql_field_len — Returns the length of the specified field
Warning
This extension is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_fetch_field_direct() [length]
- PDOStatement::getColumnMeta() [len]
說明
int mysql_field_len
( resource
$result
, int $field_offset
)mysql_field_len() returns the length of the specified field.
參數
-
result -
回傳類型為 resource 的結果集。該結果集從 mysql_query() 的呼叫中得到。
-
field_offset -
數字形式的欄位偏移量。
field_offset開始於 0。如果field_offset不存在，系統會發出E_WARNING級別的警告信息。
回傳值
The length of the specified field index on success 或者在失敗時回傳 FALSE.
範例
Example #1 mysql_field_len() example
<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
echo 'Could not run query: ' . mysql_error();
exit;
}
// Will get the length of the id field as specified in the database
// schema.
$length = mysql_field_len($result, 0);
echo $length;
?>
註釋
Note:
為了保證向前相容，可以使用下面的別名，但不贊成使用它： mysql_fieldlen()
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User Contributed Notes 2 notes
rvwoens at gmail dot com ¶
12 years ago
adam_nospam_hunger at yahoo dot com ¶
20 years ago
For a mysql type DECIMAL(8,4), the length is returned as 10 (M+2 as per documentation).
