Warning</b> mysql_free_result (): supplied argument is not a valid MySQL result, how to fix

Warning: Mysql_free_result (): supplied argument is not a valid MySQL result
What's wrong with that?

 
  Header (' Content-type:application/json;charset=utf8 ');
$host = ' 127.0.0.1:3307 ';
$root = ' root ';
$pwd = ' apeg1996 ';

$con = mysql_connect ($host, $root, $pwd);
if ($con = = False) {


echo "Connect database successfully!";
}

$sql = "SELECT * from user";
function Execute_data ($sql) {
$result = mysql_query ($sql);
Mysql_free_result ($result);
Mysql_close ($conn);
return $result;
}
echo Execute_data ($sql);
?>

The connection has been shown to be successful, but the error is reported.

Connect to the database successfully!

Warning:  F:\environment\WAMP\wamp5\wamp\wamp\www\test\sql.php



Warning:  F:\environment\WAMP\wamp5\wamp\wamp\www\test\sql.php

------to solve the idea----------------------
You only connected to the database system, but did not select the database to operate
mysql_select_db (' Library name ');
How else do you know that you are querying the user table in that library?

In addition, your mysql_close ($conn) is in the function, and the $conn is not passed to the function.
So there's going to be a 2nd mistake.
------to solve the idea----------------------
This post was last edited by Fdipzone on 2015-03-15 00:05:08

References:

Quote: References:

$result = mysql_query ($sql);
Switch
$result = @mysql_query ($sql) or Die (Mysql_error ());

The Web page shows the No database selected, this is not found this databases?
But I'm using the Navicat 8 for MySQL view tool.
I am here to create the database and resume the table. How should I query the tables in this database?

You don't have mysql_select_db,mysql before mysql_query. You do not know which db you need to perform the query operation.

After creating the connection, add a sentence
@mysql_select_db (' fill in the database name here', $conn) or Die (Mysql_error ());

 
      Header (' Content-type:application/json;charset=utf8 ');
    $host = ' 127.0.0.1:3307 ';
    $root = ' root ';
    $pwd = ' apeg1996 ';

    $con = mysql_connect ($host, $root, $pwd);
    if ($con = = False) {
        
    
        echo "Connect database successfully!";
    }

    @mysql_select_db (' Fill in database name ' here, $conn) or Die (Mysql_error ()); Add this sentence

    $sql = "SELECT * from user";
    function Execute_data ($sql, $conn) {//join $conn parameter
        $result = mysql_query ($sql);
        Mysql_free_result ($result);
        Mysql_close ($conn);
        return $result;
    }
    Echo Execute_data ($sql, $conn);
?>

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