SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Function toTypeName (children 1)
     ExpressionList (children 1)
      Identifier key
    Function toTypeName (children 1)
     ExpressionList (children 1)
      Identifier value
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 2)
         SelectQuery (children 1)
          ExpressionList (children 2)
           Literal UInt64_1 (alias key)
           Literal \'\' (alias value)
         SelectQuery (children 1)
          ExpressionList (children 2)
           Function toUInt64 (alias key) (children 1)
            ExpressionList (children 1)
             Literal UInt64_2
           Function toNullable (alias value) (children 1)
            ExpressionList (children 1)
             Literal \'\'
