当传递UPDATE查询时,mysql_query()返回boolean TRUE表示成功,否则返回FALSE表示失败,而mysql_num_rows()仅接受结果集资源作为其参数.为了确定UPDATE查询影响了多少行,请以连接资源作为参数调用mysql_affected_rows().

它并没有引起您现在遇到的问题,但是非常建议您在mysql_query()调用中附加或死掉(mysql_error()),以便捕获发生的任何MySQL错误.甚至建议您完全放弃mysql_ *函数,而转而使用PHP PDO扩展,如PHP手册中所建议的那样,并且这样做实际上不会招致更多的认知开销,以换取它在功能和性能上的巨大好处.安全.

抛开这些,下面是我如何更改您的代码,使其行为更像您所想的那样：

// obtain a database connection

$dbConn = mysql_connect($serverName, $user_name, $password)

or die("Cannot connect to server: " . mysql_error() . "
\n");

// mysql error number rarely adds enough information to be worth including

// select the database

mysql_select_db($db_name, $dbConn)

or die("Couldn't select $db_name: " . mysql_error() . "
\n");

// obtain escaped versions of query data for inclusion in update query

// it is imperative to use mysql_real_escape_string() or equivalent if you're

// going to use mysql_* functions instead of the far preferable PDO

// prepared statements; if you don't escape your data, you leave open the

// possibility of SQL injection, which someone will certainly soon use to

// screw up your website horribly

$id = mysql_real_escape_string($_GET['id']);

$additional_notes = mysql_real_escape_string($_GET['additional_notes']);

// assemble query to pass to mysql_query()

// no need for parentheses around the string; in fact i'm surprised that

// didn't result in a parse error

// also FYI re backticks, MySQL uses them to denote literal database/table/

// column names -- they're optional unless required to disambiguate between

// an entity name and a reserved word. for example, you can create a table

// containing a column named 'key', which is a MySQL reserved word, but you

// thereafter must refer to that column as `key`, with backticks, in any

// queries, to hint to MySQL's parser that you mean the column by that name

// and not the reserved word; otherwise, it's a parse error.

$sql = "UPDATE `rmstable2` SET `additional_notes` = '$additional_notes' WHERE `id` = '$id'";

// actually run the query

// this being an UPDATE query, the result is boolean and offers no

// additional useful information, so you need not capture it in a variable;

// the 'or die' clause will fire if it's false, and if it's true, you'll

// use mysql_affected_rows() to get the additional info you need.

mysql_query($sql)

or die(mysql_error());

// if the query failed, the script die()d on the previous line and didn't

// get here; if it did get here, you know the query succeeded

$resultcount = mysql_affected_rows($dbConn);

// this is technically correct but semantically odd; since you already included

// the 'additional_notes' value in the previous UPDATE query, and since

// that query certainly succeeded if we're evaluating this code at all,

// why run the same query again?

if ($resultcount == 1) {

mysql_query("UPDATE `rmstable2` SET `additional_notes` = '$additional_notes' WHERE `id` = '$id'")

or die(mysql_error());

}

// again, the 'or die' clauses mean that we can only have reached this point

// if the queries succeeded, so there's no need for an if() test here

echo "Update Successful!";

echo '

Your case has been updated.

';

// note the backslashes before the embedded double quotes; single quotes in

// tag attributes are technically invalid but most browsers will accept them,

// but you can use double quotes within a double-quoted string if you precede

// the embedded quotes with backslashes (called "escaping") to indicate that

// they're not to be taken as the end of the string

// (i.e., "\"\"" == '""')

echo "To see your changes please click here";

?>