使用PHP比较数据库中的值

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);

?>

Answer 1

1. Put the if inside the while loop
2. 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 ), ie :

---

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

Answer 2

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')

Answer 3

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

索引是文本。