Read single value from database and save it in variable

Question

I have this tiny table in my database:

----------------------
id | name      | value
----------------------
1  | test.flag | 0
----------------------
2  | username  | franz
----------------------

I simply try to read the value of test.flag and store the result into a variable.

<?php
    
    $servername = "127.0.0.1";
    $username   = "test";
    $password   = "test123";
    $dbname     = "testdb";

    $conn = mysqli_connect($servername, $username, $password, $dbname);
    
    if (!$conn) { 
        die("Connection to database failed with error#: " . mysqli_connect_error()); 
    }   
    
    $sql = "SELECT value FROM mytable WHERE name='test.flag';";
    $result = mysqli_query($conn, $sql);

    echo "<p>".$result."</p><br>";

    if (mysqli_query($conn, $sql)) {
        echo "<p>Sucessfully</p><br>";
    } else {
        echo "Error: " . $sql . "<br>" . mysqli_error($conn);
    }
    
    echo "<p>".$sql."</p><br>";
?>

But all it does is loading a blank page after I execute this script.

DirtyBit · Accepted Answer · 2015-09-26 18:28:56Z

5

You need to fetch the row and then echo it.

$result = mysqli_query($conn, $sql);
$row = mysqli_fetch_assoc($result);
echo "Result: " . $row['value'];

answered Sep 26, 2015 at 18:28

DirtyBit

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Brian Tompsett - 汤莱恩 · Accepted Answer · 2015-10-08 09:42:34Z

2

The value of the query is not stored in the $sql variable.

Like @user5173426 answered, you have to fetch it first.

Example (http://www.w3schools.com/php/php_mysql_select.asp):

while($row = $result->fetch_assoc())
   $toEcho = $row["value"];
echo $toEcho;

edited Oct 8, 2015 at 9:42

Brian Tompsett - 汤莱恩

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answered Sep 26, 2015 at 18:30

Jonathan Lam

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1 Comment

DirtyBit Over a year ago

Ahh, I love it when I see my name being used as a reference. ;-)

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