SelectWithUnionQuery (children 2)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 2)
    Identifier theAlias
    Function CAST (alias src) (children 1)
     ExpressionList (children 2)
      Literal NULL
      Literal \'Nullable(String)\'
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier alias_bug_dist
   Literal UInt64_1
 Identifier Null
