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)
           Function toDecimal64 (alias key) (children 1)
            ExpressionList (children 2)
             Literal UInt64_2
             Literal UInt64_8
           Function toNullable (alias value) (children 1)
            ExpressionList (children 1)
             Literal \'\'
         SelectQuery (children 1)
          ExpressionList (children 2)
           Function toDecimal32 (alias key) (children 1)
            ExpressionList (children 2)
             Literal UInt64_2
             Literal UInt64_4
           Function toFixedString (alias value) (children 1)
            ExpressionList (children 2)
             Literal \'\'
             Literal UInt64_1
