please hellp

I need to do the action "SELECT transferid,SUM(despoit-transferAmount) AS money from money_transfer" WHERE userid=$_SESSION[userid].

the userid is in the users table.

how do I combined the two tables so the action will work?

 

Why not you are fetching first users table if its in table.

$select = SELECT userid from users WHERE username="name" OR Other=othercondition LIMIT 1
Then fetch it
$row = mysqli_fetch_assoc ($select);
$_SESSION[userid] = $row["userid"]; (No Need to do this) because you can put $row["userid"] directly in condition.
Then process your statement
SELECT transferid,SUM(despoit-transferAmount) AS money from money_transfer" WHERE userid=$_SESSION[userid] (or userid=$row["userid"])

I think its very simple ..... Or you have describe a bit more about your code because according to your details its very simple for me because users table is already in database so can fetch very easily.

 

this is how I write the code but it dosent work:

$mysqli = new mysqli("localhost","root",'',"bank");

if ($mysqli -> connect_errno) {
echo "Failed to connect to MySQL: " . $mysqli -> connect_error;
exit();
}

$select = "SELECT userid from users WHERE userid=$_SESSION[userid] LIMIT 1";
$row = mysqli_fetch_assoc ($select);
$sql= "SELECT transferid,SUM(despoit-transferAmount) AS money from money_transfer WHERE userid=$_SESSION[userid] )"

if ($result = $mysqli -> query($sql)) {

while ($obj = $result -> fetch_object()) {
printf($obj->money."$");
}
$result -> free_result();
}

$mysqli -> close();

 

Why are you fetching data from users table while using $_SESSION["userid"] in both statement. Your first statement to get record from users are completely useless.

And because you are fetching two values from money_transfer table so need to define it that what you want to print there. Take a look at www. w3schools. com/pHp/func_mysqli_free_result.asp

 

nothing helps.
I'm desperate .