MySQL query with output to PHP page

Question

I am trying to make simple page which will return values from MySQL table, but the problem is that if I want to use condotions in query then it doesn't work.

My PHP page:

    <?php
$servername = "10.10.10.10";
$username = "username";
$password = "password";
$dbname = "GENERIC_TABLES";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
     die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT WO_NUM+1 from GENERIC_TABLES.WO_NUMBERS ORDER BY WO_NUM DESC limit 1";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
     // output data of each row
     while($row = $result->fetch_assoc()) {
         echo "<br> WO Number ". $row["WO_NUM"]. "<br>";
     }
} else {
     echo "0 results";
}
$conn->close();
?>

So, WO_NUM column has numbers like 1, 2, 3 etc. I want to get the last one + 1 So if I do like:

$sql = "SELECT WO_NUM from GENERIC_TABLES.WO_NUMBERS ORDER BY WO_NUM DESC limit 1";

Then it works fine, but if I want to make it WO_NUM + 1 then it returns nothing.

Why it happens like that and is there any way to get what I want using MySQL? I don't want to get WO_NUM and then using PHP make it + 1, since I also need INSERT to the table values and I would like to understand why it doesn't work.

SELECT max(WO_NUM)+1 as NEW_NUM from GENERIC_TABLES.WO_NUMBERS ??? — AbraCadaver
– AbraCadaver, Commented Oct 21, 2016 at 16:39
Exactly! I didnt take into mind that if I use WO_NUM + 1, it changes column name, that is why it didn't give any result..Using Alias solved problem. Thanks you very much @AbraCadaver, saved my time by pointing to this... — Roman
– Roman, Commented Oct 21, 2016 at 16:47

AbraCadaver · Accepted Answer · 2016-10-21 16:49:32Z

1

As you realized, WO_NUM+1 changes the column name in the resulting array, so use an alias WO_NUM+1 as NEW_NUM. However I would not bother with the sorting and limit. Consider MAX():

SELECT max(WO_NUM)+1 as NEW_NUM from GENERIC_TABLES.WO_NUMBERS

answered Oct 21, 2016 at 16:49

AbraCadaver

79.2k7 gold badges75 silver badges91 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Roman · Accepted Answer · 2016-10-21 16:49:04Z

0

As it has been pointed by AbraCadaver, I missed that if I am using WO_NUM + 1 then column name changing so that is why i didn't get any output, so using alias solved problem.

answered Oct 21, 2016 at 16:49

Roman

1076 bronze badges

1 Comment

Nana Partykar Over a year ago

Please accept @AbraCadaver Answer, if it helped you.

Collectives™ on Stack Overflow

MySQL query with output to PHP page

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related