Is it possible to update a table using WHERE email = $_SESSION['email'] - php

Question

I want to update an already existing table it only has email and I want to add first name and last name does this code work to do so?
UPDATE table
SET fname='$fname', lname='$lname'
WHERE email= '$_SESSION['email'].';
Or can I also use this
$sql="INSERT INTO $tbl_name(fname, lname)VALUES( '$fname, $lname')" WHERE email= '$_SESSION['email'].';

Answer 1

Your UPDATE has a syntax error (problem with apostrophes.)
INSERT will not update but multiply rows. That is not what you want to have.
Here is my suggested query:
$sql="UPDATE table SET fname='$fname', lname='$lname' WHERE email='".$_SESSION["email"]."'" ;

Answer 2

Fix your quotes, like so:
$sql="INSERT INTO $tbl_name(email) VALUES ( '" . $email . "') WHERE email = '" . $_SESSION['email'] . "'";

Answer 3

Try like this: In case of simple Update Query
$user_email = $_SESSION['email'];
$fname = 'Thierry';
$lname = 'Henry';
UPDATE table
SET fname='$fname', lname='$lname'
WHERE email= '$user_email';
Insertion is not a good idea here. It might duplicate your records.
If you want to be more specific than Go like this: Just providing your general syntax. No real time Syntax:
$user_email = $_SESSION['email'];
$fname = 'Thierry';
$lname = 'Henry';
$check_user = 'SELECT * FROM table WHERE email = "user_email"';
if($check_user)
{
YOUR UPDATE QUERY
}
else
{
YOUR INSERT QUERY
}

Answer 4

In case you are using mysql_ functions you should also escape the input:
$email = mysql_real_escape_string($_SESSION['email']);
Disclaimer for idiots: This does not imply I suggest to use mysql_* functions. Use mysqli or PDO instead.
You should also check against NULL and empty values in your query.
$sql = "REPLACE INTO " . $table . "
SET email='" . $email . "'
WHERE email='" . $email . "'
AND email IS NOT NULL
AND email != ''";
From http://dev.mysql.com/doc/refman/5.0/en/replace.html:
REPLACE works exactly like INSERT, except that if an old row in the
table has the same value as a new row for a PRIMARY KEY or a UNIQUE
index, the old row is deleted before the new row is inserted.
Please don't downvote if this doesn't exactly fit, just use INSERT or UPDATE with the same syntax then.