DescribeQuery (children 1)
 TableExpression (children 1)
  Subquery (children 1)
   SelectWithUnionQuery (children 1)
    ExpressionList (children 1)
     SelectQuery (children 2)
      ExpressionList (children 2)
       Function CAST (alias a) (children 1)
        ExpressionList (children 2)
         Function tuple (children 1)
          ExpressionList (children 1)
           Literal UInt64_1
         Literal \'Tuple (id UInt64)\'
       Function arrayMap (children 1)
        ExpressionList (children 2)
         Function lambda (alias untupled_value) (children 1)
          ExpressionList (children 2)
           Function tuple (children 1)
            ExpressionList (children 1)
             Identifier x
           Function untuple (children 1)
            ExpressionList (children 1)
             Identifier a
         Literal Array_[UInt64_1, UInt64_2, UInt64_3]
      TablesInSelectQuery (children 1)
       TablesInSelectQueryElement (children 1)
        TableExpression (children 1)
         TableIdentifier test_table