PHP和mysql查询带有动态变量

Question

I am trying to get a value from database using the code below. I want to save the value in the variable category so I can give this as parameter to a function. The id is dynamically given. Is the code below correct? because when trying this nothing works...

$thecategory = mysql_query("SELECT TYPE FROM lists WHERE id =" . this.id);

Answer 1

The use of '$id' provides a little security against sql injection

$thecategory = mysql_query("SELECT `TYPE` FROM `lists` WHERE `id` ='$id'");
$associate = mysql_fetch_assoc($thecategory);
$TYPE = $associate['TYPE'];

Answer 2

Use mysql_result :

$thecategory = mysql_query("SELECT TYPE FROM lists WHERE id =" . $id); // changed $id
$type = mysql_result($thecategory, 0);

I suggest that you use PDO instead of mysql_* functions, they are deprecated.

Answer 3

Try:

$thecategory = mysql_query("SELECT TYPE FROM lists WHERE id =" . this->id);