email validation one condition & more than one else statement in PHP - php

Question

I will try to put email validation with have more than one case.
First(if):email is required.
Second(if): invalid format of email.
Third(else): Email is exist(Active User)
Fourth(else): Email is in approve(Admin is not approved account yet so its
still in request table)
Fifth(else):Everything goes well,post the data into database.
I try to solve this by if-else statement but in last two case I do not have any condition its just have to pass that validation.I also try switch statement, but it's not go after the first case:
Here is my validation:
if(empty($_POST['email']))
{
$email=$_POST['email'];
$emailError="Email is required";
$error=true;
}
else
{
$email=$_POST['email'];
if(!filter_var($email, FILTER_VALIDATE_EMAIL))
{
$emailError = "Invalid email format";
$error=true;
}
else
{
$sql="SELECT * FROM user WHERE email='$email'";
$res=mysqli_query($db,$sql);
if (mysqli_num_rows($res) > 0)
{
$emailError = "Email already exists";
$error=true;
}
}
else
{
$sl="SELECT * FROM request WHERE email='$email'";
$ress=mysqli_query($db,$sl);
if (mysqli_num_rows($ress) > 0)
{
$emailError = "Your Accout is in process";
$error=true;
}
}
}

Answer 1

Following is the way to do this:
Declare some random variables for each error
By using the multiple if conditions make a first check if it is empty or not. Made a second check if it's match the correct format, third if value exist in db or not
I'm displaying the sample code for this
if(empty($_POST['email'])){
$emptyMail = 'Please provide the Email';
}else{
$notEmpty= 1;
}
if(!){ //check the preg match
wrongFromat = 'Please enter the Mail in correct format';
}else{
$correctFormat = 1;
}
if($notEmpty= 1 && $correctFormat = 1){ //check the database
//if it exist in db
$exist = 0;
}elseif($notEmpty= 0 || $correctFormat = 0 || $notEmpty= 1 || $correctFormat = 1){
$exist = 0;
}else{
$exist = 1;
}
if($notEmpty= 1 && $correctFormat = 1 $exist = 1){
//insert in database and send the status pending to the user
}

Answer 2

In line 1 you check if(empty($_POST['email'])),
so if it is empty you should return error, instead you try to save empty value in line 3 and so on.

Answer 3

ok I put the condition for $error & now its working fine. remember that you have to put $exist=""; in starting.
here is my code:
if(empty($_POST['email']))
{
$email=$_POST['email'];
$emailError="Email is required";
$error=true;
}
else {
$email=$_POST['email'];
if(!filter_var($email, FILTER_VALIDATE_EMAIL))
{
$emailError = "Invalid email format";
$error=true;
}
else
{
$sql="SELECT * FROM user WHERE email='$email'";
$res=mysqli_query($db,$sql);
if (mysqli_num_rows($res) > 0)
{
$emailError = "Email already exists";
$error=true;
$exist=1;
}
}
if($exist!=1)
{
$sl="SELECT * FROM request WHERE email='$email'";
$ress=mysqli_query($db,$sl);
if (mysqli_num_rows($ress) > 0)
{
$emailError = "Your Accout is in process";
$error=true;
}
}
}