convert Nested array into mysql query

$fields=array();
$values=array();
for($i=0;$i<count($array);$i++)
{
   $fields[]=$array[$i]['field_name'];
   $values[]=$array[$i]['field_value'];
}

if(count($array) > 0)
{
   $query="Insert into tablename (".implode(",", $fields).") values (".implode(",", $values).")";
   mysql_query($query);
}

You need to ensure that your values are correct and protected to avoid SQL Injection. Building dynamically your own SQL query and inserting directly in your database is not safe.

Anyway you can use array_map() to do something like this:

$arr = array(array("name" => "column1", "value" => "value1"),
             array("name" => "column2", "value" => "value2"),
             array("name" => "column3", "value" => "value3"));

$columns = array_map(function($item) { return $item['name'];}, $arr);
$values = array_map(function($item) { return "'". $item['value'] . "'";}, $arr);


$columnsList = implode(',', $columns);
$valuesList = implode(',', $values);

$sql = "INSERT INTO mytable($columnsList) VALUES ($valuesList)";

EDIT: As said in introduction this would not be safe and it would be better to use MySQLi or PDO. But you would also need to know the type of the column you want to insert into.

Try this

$sql = "INSERT INTO `table_name` SET ";
$sql_fields='';

foreach($array_name as $k=>$v){
    $sql_fields .= "`".$v['field_name']."`='".$v['field_value']."', ";
}

$sql_fields = substr($sql_fields,0,-2);
$sql .= $sql_fields;
echo $sql;

A very simple approch would be this :

$query = 'insert into table ';
foreach($inputs as $input) {
  $query .= ' '.$input['field_name'].' = '.$input['field_value']; 
}
echo $query;