code: function  buildSqlFilter(filter, columns)  {
  	if (filter.op === 'and')  {
  		var  clones = [];
  		filter.filters.forEach(function(f) {
  			var  cf = buildSqlFilter(f, columns);
  			if (cf)
  				clones.push( cf );
  		});
  		
  		var  len = clones.length;
  		if (len < 1)
  			return null;
  		else
  			return  len > 1  ?  {op: 'and', filters: clones} : clones[0];
  	}
  	else  if (filter.op === 'or')  {
  		var  clones = [];
  		filter.filters.forEach(function(f) {
  			var  cf = buildSqlFilter(f, columns);
  			if (cf)
  				clones.push( cf );
  		});
  
  		return  clones.length === filter.filters.length  ?  {op: 'or', filters: clones} : null;
  	}
  
  	var  cf = null,
  		 colName = filter.name;
  	if (columns.indexOf(colName) >= 0)
  		cf = filter; //cloneObj( filter );
  
  
  	return  cf;
  }
docs: Build a new SQL filter with 'inertia' columns