Checking if value returned is empty

Question

I have a simple PHP file in which I check if the users email exists in my database using the following code:

   $query = "SELECT * FROM userData WHERE email = '$email'";
   $result = mysql_query($query);

Which works perfectly fine when the user enters an email address that is in the database, however, when I want to determine if this $query is null or empty - I'm not sure which one though.

When I enter an email that isn't in the database and add the following code in below:

    if(is_null($result)){
    echo 'email not in database';
    }

the code in the {} isn't executed.

I was just wondering if you could help me out.

Hi again,

Sorry for the duplicating another post. I corrected it by using:

if(mysqli_num_rows($result) > 0)
{ 
  // a row with email exists 
} 
else 
{
  // no row with particular email exists 
}

`mysql_query` returns the executed query resource. You have to fetch data from resource or count the rows for that. — Sougata Bose, Jun 23 '15 at 13:06
Obligatory [don't use mysql_*](https://stackoverflow.com/questions/60174/how-can-i-prevent-sql-injection-in-php?rq=1) functions, especially if you're new :), swap over to something better now and save yourself hours of headache later on — SubjectCurio, Jun 23 '15 at 13:07
Just a warning, this is vulnerable to [SQL injection](https://en.wikipedia.org/wiki/SQL_injection) — Gray, Jun 23 '15 at 13:11
there's a big difference between `is_null` and `empty`, especially in MySQL and doing a SELECT all. what you're looking for is `mysql_num_rows()` or `COUNT()`. — Funk Forty Niner, Jun 23 '15 at 13:14

Praveen D · Answer 1 · 2015-06-23T13:14:09.817

0

Try this

$row = mysql_fetch_rows($result);
if(!$row){
      echo 'email not in database';
}

OR

$num = mysql_num_rows($result);

 if($num == 0){                                                         
    echo 'email not in database';
    }

edited Jun 23 '15 at 13:14

answered Jun 23 '15 at 13:06

Praveen D

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Meenesh Jain · Answer 2 · 2015-06-23T13:13:10.753

0

You can directly check whether your query executed or not by

 if($result > 0){
    // perform some action 
 }

You should use mysqli_ instead of mysql_ as it is deprecated and will be removed in future.

what you need is mysqli_num_rows() to see if atleast 1 row was in the table or not

for reference - num_rows

if(mysqli_num_rows($result) > 0)
{ 
  // a row with email exists 
} 
else 
{
  // no row with particular email exists 
}

edited Jun 23 '15 at 13:13

answered Jun 23 '15 at 13:08

Meenesh Jain

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You should clarify that you're switching from mysql to mysqli functions (which is the right thing to do). – Geoff Atkins Jun 23 '15 at 13:10
Making edit to my answers – Meenesh Jain Jun 23 '15 at 13:11

score 0 · Answer 3 · edited Jun 23 '15 at 13:26

0

You can try this too !

if(empty($result)){
    echo 'email not in database';
}

empty() will check if $result is null, or its value is 0, or if $result doesn't exists.

See here : http://php.net/manual/fr/function.empty.php

edited Jun 23 '15 at 13:26

Mike

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answered Jun 23 '15 at 13:11

faflo10

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Checking if value returned is empty

3 Answers3