简单的MySQL查询不起作用

Question

I have this very simple function:

function getCatName($id){
$sql = "SELECT * FROM biznet_category WHERE ID ='".$id."';";
$res = mysql_query ($sql) or die (mysql_error ());
$row = mysql_fetch_assoc ($res);
$name = $row["Name"];
return $name;
}

So with this function I should be able to get the category name, but it doesn't work with the parameter. If I put 8 or 9, the categoryname is displayed correctly.

The id is also passed on like it should, when I print it out, it shows 8 or 9.

I know the solution is quite simple, I just don't see it.

Answer 1

To fix remove the quotes and check the column name for case id or ID. Since the query string is in double quotes you don't have to use the . join

$sql = "SELECT * FROM biznet_category WHERE ID = $id";

You can use curly brackets which I find easier to read

$sql = "SELECT * FROM biznet_category WHERE ID = {$id}";

If you were querying a string rather than an integer you can simply do

$sql = "SELECT * FROM biznet_category WHERE ID = '{$id}'";

Answer 2

$sql = "SELECT * FROM biznet_category WHERE ID ='".$id."';";

至

$sql = "SELECT * FROM biznet_category WHERE ID = ".$id;

Answer 3

尝试这个

$sql = "SELECT * FROM biznet_category WHERE ID = ".$id;

Answer 4

列名ID的拼写是否正确？