docs: @Nullable
    public static Granularity toQueryGranularity(final DruidExpression expression, final ExprMacroTable macroTable)
    {
      final TimestampFloorExprMacro.TimestampFloorExpr expr = asTimestampFloorExpr(expression, macroTable);
  
      if (expr == null) {
        return null;
      }
  
      final Expr arg = expr.getArg();
      final Granularity granularity = expr.getGranularity();
  
      if (ColumnHolder.TIME_COLUMN_NAME.equals(Parser.getIdentifierIfIdentifier(arg))) {
        return granularity;
      } else {
        return null;
      }
    }