SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 1)
    Function sum (children 1)
     ExpressionList (children 1)
      Identifier b
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier t_multi_prewhere
   Function less (children 1)
    ExpressionList (children 2)
     Identifier a
     Literal UInt64_5000
