SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Identifier b1
   TablesInSelectQuery (children 2)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier tab1
    TablesInSelectQueryElement (children 2)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 2)
          ExpressionList (children 1)
           Asterisk
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier tab2
     TableJoin (children 1)
      Function equals (children 1)
       ExpressionList (children 2)
        Function toInt32 (children 1)
         ExpressionList (children 1)
          Function plus (children 1)
           ExpressionList (children 2)
            Identifier a1
            Literal UInt64_1
        Identifier a2