CODEWITHSUNDEEP
phpmysql
bumbledy
bumbledy

Reputation: 85

mysqli_query gives null result php

I am trying to interrogate a database, but mysqli_query($dbc, $query) always returns {"current_field":null,"field_count":null,"lengths":null,"num_rows":null,"type":null} I do not have any var_dump in the code. 

$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

if (mysqli_connect_errno()){
    trigger_error ('Could not connect to MySql: ' . mysqli_connect_error());
    echo "it had an error";
} else {
    mysqli_set_charset($dbc, 'utf8');
    echo "it connected";
}

this echoes "it connected"

function getGames($dbc){           
    $query="SELECT * FROM games WHERE min_players <= ".$number." AND max_players >=".$number.";";         
    $result = mysqli_query($dbc, $query) or trigger_error("Query: $query\ n<br />MySQL Error: " . mysqli_error($dbc));

    if(mysqli_affected_rows($dbc)) {
        return $result;
    } else {
        return "no affected rows";
    }
}

When I run my query in phpMyAdmin, I get several lines of results.

Also, the function doesn't return "no affected rows" when it is called:

$result = getGames($dbc);
echo json_encode($result);

Upvotes: 1

Views: 5078

Answers (2)

Dapper Dan
Dapper Dan

Reputation: 1062

I just changed your mysqli_affected_rows($dbc) to mysqli_num_rows($result), and works for me. mysqli_affected_rows($dbc) Returns the number of rows affected by the last INSERT, UPDATE, REPLACE or DELETE query.

function getGames($dbc){
$query="SELECT * FROM games WHERE min_players <= ".$number." AND max_players >=".$number.";";
$result = mysqli_query($dbc, $query) or trigger_error("Query: $query\ n
MySQL Error: " . mysqli_error($dbc));

if(mysqli_num_rows($result)) {
    return $result;
} else {
    return "no affected rows";
}

}

Upvotes: 1

jterry
jterry

Reputation: 6269

Unless you're declaring $number globally, it won't be available in the scope of getGames. You should pass it in:

function getGames($dbc, $number) {
    // ...

Additionally, you could output the exact SQL that you're running so you can test it in phpMyAdmin (and so you can verify that $number is correctly being passed to your function):

echo $query;

Finally, mysqli_affected_rows doesn't return the number of rows in SELECT statements. Try mysqli_num_rows instead:

$sql = sprintf('Your SELECT statement with %d number', $number);
echo $sql; // To visually verify the SQL is valid

$query = mysqli_query($dbc, $sql);

if (false !== $query) {
    return mysqli_num_rows($query);
} else {
    return mysqli_error($dbc);
}

Upvotes: 2

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