AlterQuery  table_with_string_key (children 2)
 ExpressionList (children 1)
  AlterCommand MODIFY_COLUMN (children 1)
   ColumnDeclaration int_key (children 1)
    DataType Enum8 (children 1)
     ExpressionList (children 2)
      Function equals (children 1)
       ExpressionList (children 2)
        Literal \'y\'
        Literal UInt64_1
      Function equals (children 1)
       ExpressionList (children 2)
        Literal \'x\'
        Literal UInt64_2
 Identifier table_with_string_key
