-[NSNull length]: unrecognized selector sent to instance 0x2689678 2013-07-30 15:36:21.984 Pretyum[5006:c07]

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return displayObject.count;
}


// TableView

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";    
    Vendor_Home_Cell *cell = (Vendor_Home_Cell *) [tableView dequeueReusableCellWithIdentifier : CellIdentifier];    
    
    if (cell == nil) {
           NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"Vendor_Home_Cell" owner:self options:nil];
        cell = [nib objectAtIndex:0];
     
    }
    
    NSDictionary *tmpDict = [displayObject objectAtIndex:indexPath.row];
    
    cell.lblposition.text = [tmpDict objectForKey:position];
    cell.lbljobid.text = [tmpDict objectForKey:jobid];
    cell.lblskills.text = [tmpDict objectForKey:skills];
    cell.lbllocation.text = [tmpDict objectForKey:city];
    cell.lblstate.text = [tmpDict objectForKey:state];
    cell.lblrate.text = [tmpDict objectForKey:rate]; 


    cell.lblskills.numberOfLines = 0;
    cell.lblskills.lineBreakMode = NSLineBreakByWordWrapping;
    
    cell.lblposition.numberOfLines = 0;
    cell.lblposition.lineBreakMode = NSLineBreakByWordWrapping;
    
   
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    
   
    return cell;    
}


- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return 205.0f;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    
    
    NSDictionary *tmpDict = [displayObject objectAtIndex:indexPath.row];
    Vendor_Job_Details *detail = [[Vendor_Job_Details alloc] init];
    detail.sJobID = [tmpDict objectForKey:jobid];
    detail.sUser_id = _sUser_id;
    [self.navigationController pushViewController:detail animated:YES];
    [tableView deselectRowAtIndexPath:indexPath	animated:YES];

       }

<?php
	$objConnect = mysql_connect("localhost","root","");
	$objDB = mysql_select_db("sample");
	$strSQL = "SELECT * FROM sample_admin WHERE 1 ORDER BY job_id DESC";
	$objQuery = mysql_query($strSQL);
	$intNumField = mysql_num_fields($objQuery);
	$resultArray = array();
	while($obResult = mysql_fetch_array($objQuery))
	{
		$arrCol = array();
		for($i=0;$i<$intNumField;$i++)
		{
			$arrCol[mysql_field_name($objQuery,$i)] = $obResult[$i];
		}
		array_push($resultArray,$arrCol);
	}
	
	mysql_close($objConnect);
	
	echo json_encode($resultArray);
?>

if (DESC == [NSNull null]) {
    // DESCis null
}