Glad to see you're trying out those new functions.  We have a built-in ZenDB function for that now: 

DB::tableExists($table)

Which does this internally: 

public static function tableExists(string $tableName): bool
{
    $fullTable = self::getFullTable($tableName);
    return self::query("SHOW TABLES LIKE ?", $fullTable)->count() > 0;
}

You can pass it a table with or without a table prefix, and it will add one if needed.

Hope that helps! Let me know any other questions.

function testIfTableExists($table)
{
    global $TABLE_PREFIX;

    $sql = "SHOW TABLES LIKE '$TABLE_PREFIX$table'";
    $val = mysqli()->query($sql);
    return mysqli()->affected_rows > 0 ? true : false;
}

I am trying to update it to DB::query($sql), but the result is an empty array. Running the query in the MySQL console shows a single result with the table name. 

Using ZenDB, what would be the recommended way to test if a table exists?

Instead of reinventing the wheel, is there a CMSB function determining whether a table exists?