SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Subquery (alias a) (children 1)
     SelectWithUnionQuery (children 1)
      ExpressionList (children 1)
       SelectQuery (children 1)
        ExpressionList (children 1)
         Function plus (children 1)
          ExpressionList (children 2)
           Function now (children 1)
            ExpressionList
           Function sleep (children 1)
            ExpressionList (children 1)
             Literal UInt64_1
   ExpressionList (children 1)
    Function equals (children 1)
     ExpressionList (children 2)
      Identifier a
      Identifier a
