使用括号填充数组值以执行插入

I want to have each array value inside a paranthesis

$id   = $_POST['id'];
$test2 = array($id);
$id_list = implode(',', $test2);
$sql .= "INSERT INTO tmp (id) VALUES ({$id_list});";

for example: I'm performing an insert so the output of the list should be (5),(10),(15) not '5','10','15'

Any suggestions on how I can insert using an array?

MySQL's extended insert syntax is

INSERT INTO sometable (...fields...) VALUES (value set #1), (value set #2), (value set #3), etc...

Note how each value set is in its own (). You're not doing that. you're just passing a bunch of values in a SINGLE () set, which means you're providing values for fields that are NOT present in the field list.

You need to do

$id_list = '(' . implode('),(', $_POST['id']) . ')';

producing

(5),(10),(15)

instead of

(5, 10, 15)

You also need to realize that you're vulnerable to sql injection attacks.