mysql用条件删除查询

i have this query .. Delete in more than one table .. but If there a field does not have content in any table, it does not delete anything

$sql = " DELETE 
            property,
            unit,
            maintenance,
            report,
            owner
         FROM 
            property,
            unit,
            maintenance,
            report,
            owner           
        WHERE 
            property.id = '".$_REQUEST['property']."'
        AND
            unit.property = property.id
        AND
            unit.id = maintenance.unitid
        AND 
            report.maintenance = maintenance.id 
        AND 
            property.id = owner.property 
        "; 

SO , what conditions can i use it in the query to skip this problem ..

You will want to look at transactions for this. This is a typical (but costly ) way to perform this kind of operation.

Alternatively, you could create a stored procedure and check that all the criteria are appropriate before executing the delete.