尝试使用PHP将MySQL查询导出为CSV

Question

I'm getting a warning

Warning: mysql_fetch_assoc() expects parameter 1 to be resource, array given

when trying to export a MySQL query result as CSV using PHP code like this:

public static function exportLocationCSV($id){
        $sql =<<<EOF
            SELECT col1, col2, col3
            FROM table1
            JOIN table2 ON table1.col0=table2.col0 
            WHERE table1.col0 = $id;
EOF;


        // output headers so that the file is downloaded rather than displayed
        header('Content-Type: text/csv; charset=utf-8');
        header('Content-Disposition: attachment; filename=data.csv');

        // create a file pointer connected to the output stream
        $output = fopen('php://output', 'w');

        // output the column headings
        fputcsv($output, array('Column 1', 'Column 2', 'Column 3'));

        $query_export= self::$db_connection->query($sql);
        $rows = array();
        while($r = mysqli_fetch_assoc($query_export)){
            $rows[] = $r;
        }

        // loop over the rows, outputting them
        while ($row = mysql_fetch_assoc($rows)) fputcsv($output, $row);
}

Answer 1

You're mixing mysql_* and mysqli_* API's. mysql_fetch_assoc() will not work with the mysqli_ API. Your second while loop is the one using the wrong function call.

This line:

// loop over the rows, outputting them
while ($row = mysql_fetch_assoc($rows)) fputcsv($output, $row);

should be change to the correct function call:

// loop over the rows, outputting them
foreach($rows AS $row) fputcsv($output, $row);

Answer 2

mysql_fetch_assoc used to fetch a result row as an associative array here is more about mysql_fetch_assoc

what you are trying to do is to pass $rows which is array while mysql_fetch_assoc expecting you to pass mysql_query