Comparing values in a database with PHP

Question

I was wondering how I could compare a value/varchar in my database to a string in my own PHP script. Below is a picture of my database if it helps and I just want to compare the value inside the ThunderOrNot column (ID = 1) to a string of "Thunder". Neither of my bottom 2 'if' statements work. What am I doing wrong? Thanks!

    <?php

$link = mysqli_connect('.....', '.....', '.....', '.....');

$query = "select * from thunderDemo";
$result = mysqli_query($link, $query);

while($row = mysqli_fetch_array($result))
{
         echo $row["ThunderOrNot"];
}

if($row[ThunderOrNot] == 'Thunder')
{
         echo "The Value equals Thunder";
}

if($row == 'Thunder')
{
         echo "The Value equals Thunder";
}

mysqli_close($link);

?>

The only issue I have with this @PedroLobito is that PHP will try to resolve ThunderOrNot as a constant, and on finding none throws a notice and then tries to place quotes around the 'constant' itself. The warning should not stop processing the of the code, depending on how the OP's server is set up. "E_NOTICE : type 8 -- Use of undefined constant ThunderOrNot - assumed 'ThunderOrNot' The Value equals Thunder" — Jay Blanchard
– Jay Blanchard, Commented May 4, 2016 at 16:41

Community · Accepted Answer · 2017-05-23 12:23:56Z

2

Put the if inside the while loop
Add quotes to $row["ThunderOrNot"] (not as important, because an unquoted string will be interpreted as a constant by php and, in this case, its value will be ThunderOrNot (kudos:Jay Blanchard), i.e. :

while($row = mysqli_fetch_array($result))
{
    if($row["ThunderOrNot"] == 'Thunder'){
        echo "The Value equals Thunder";
    }
}

edited May 23, 2017 at 12:23

CommunityBot

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answered May 4, 2016 at 16:36

Pedro Lobito

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Comments

Julie Pelletier · Accepted Answer · 2016-05-04 16:35:19Z

1

Your main problem is that you put your conditions after there are no more records returned. Move them inside your while loop.

Note that you should add a second parameter to mysqli_fetch_array(): MYSQLI_ASSOC for it to return an associative array.

The condition would then be: if ($row['ThunderOrNot'] == 'Thunder')

answered May 4, 2016 at 16:35

Julie Pelletier

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3 Comments

Jay Blanchard Over a year ago

PHP already fetches an associative: " Fetch a result row as an associative, a numeric array, or both."

Julie Pelletier Over a year ago

It defaults to MYSQLI_BOTH which can be confusing and slower.

Julie Pelletier Over a year ago

Why do you argue for nothing? Look at the code. He loops through the records and just checks the conditions after the loop.

Jay Blanchard · Accepted Answer · 2016-05-04 16:41:41Z

-1

if($row["ThunderOrNot"] == 'Thunder')

Index is a text.

edited May 4, 2016 at 16:41

Jay Blanchard

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answered May 4, 2016 at 16:30

Stian Skjelstad

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