INSERT and UPDATE statements passing wrong data into database - php

Question

I have this DB table reset_attempts and inside it has an
id : int(10) auto_increment
reset_counter : int(10) default 1
reset_time : timestamp current_timestamp
ip : varchar(255)
and I have this simple php code
$sql = "SELECT * FROM reset_attempts WHERE ip = '$ip'";
$query = mysqli_query($db_conx, $sql);
$num_rows = mysqli_num_rows($query);
$row = mysqli_fetch_array($query);
$reset_counter = $row['reset_counter'];
$reset_time = $row['reset_time'];
if ($num_rows == 0) {
$sql = "INSERT INTO reset_attempts (reset_counter, reset_time, ip) VALUES ('1',now(),'$ip')";
$query = mysqli_query($db_conx, $sql);
} else if ($num_rows == 1) {
$reset_counter = $reset_counter + 1;
$sql = "UPDATE reset_attempts SET reset_counter = '$reset_counter', reset_time = now() WHERE ip = '$ip'";
$query = mysqli_query($db_conx, $sql);
}
This is just a piece of whole php file..this is only the problem code..of course it has the db connection and I take the ip correctly..The problem is when I hit submit it will execute the first if statement, it executes correctly except that the reset_counter value it passes it to DB always as zero and all the other fields are correctly.
When it executes the second if statement again it's not updating the reset_counter field and set it to zero. I don't know where is the problem. Maybe is so simple and I can't see it because I am searching it so much! Anyway thanks in advance!

Answer 1

As per discussion in comments (between the OP and I), the shown snippet of code works on its own and have determined that something else is causing this (in unshown full code).
Let's consider this question to be closed, until the rest of the (OP's) code can be investigated further.
Last two comments between OP and I:
Me: Ok, this is probably going to be my last suggestion, because I don't know what else could be causing this. Can you try and run that snippet on its own (your posted code), without the rest of your code, and see if it will work on its own? If it does work, then you'll know right away that something else in your full code is causing this.
OP: You are right..it was the last thought that did not came to my mid trying it pfff..the snippet works fine on it's own...so it's something else in my code as you said.. :/ I am sorry for that I didn't test it from start...at least now I know what to search..!

Answer 2

For the first time there is no record in the database for that ip so $row['reset_counter'] has value zero and you enter the value zero in the database. Then when you again submit then it fetches the same value from the database and as it enters 0 for reset_counter so when you do
$row = mysqli_fetch_array($query);
$reset_counter = $row['reset_counter'];
It fetches that row with 0 for reset_counter and update it to again zero
Update
Add these this inside else statement if you need it anywhere in your code otherwise remove this too
$reset_time = $row['reset_time'];
And remove
reset_counter = $row['reset_counter'];
Use this code
$sql = "SELECT * FROM reset_attempts WHERE ip = '$ip'";
$query = mysqli_query($db_conx, $sql);
$num_rows = mysqli_num_rows($query);
$row = mysqli_fetch_array($query);
if ($num_rows == 0) {
$sql = "INSERT INTO reset_attempts (reset_counter, reset_time, ip) VALUES ('1',now(),'$ip')";
$query = mysqli_query($db_conx, $sql);
} else if ($num_rows == 1) {
$reset_time = $row['reset_time'];
$sql = "UPDATE reset_attempts SET reset_counter = reset_counter+1, reset_time = now() WHERE ip = '$ip'";
$query = mysqli_query($db_conx, $sql);
}

Answer 3

I don't know exactly what goes wrong in your code but I think you are using too much PHP and too little MySQL. I have a couple of changes I would propose
First, most times you would do the update, right? Then I would just skip the SELECT, do the UPDATE and then ask the driver for number of rows updated. If it's 0 then do the INSERT.
Second. When you do the update just increment inside MySQL, no need to do that in PHP.
UPDATE reset_attempts SET reset_counter = reset_counter+1, reset_time = now() WHERE ip = '$ip';
Otherwise two parallel calls your page might just count as one in the database.
Third, if you reset_counter isn't already an integer change it. From your code it looks like it's a char or varchar and it just doesn't make any sense to store a counter as text.