SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Function toDateTime64 (alias ts) (children 1)
     ExpressionList (children 3)
      Literal \'1970-01-01 22:31:08\'
      Literal UInt64_6
      Literal \'UTC\'
    Function toUnixTimestamp64Micro (alias microseconds_since_day_start) (children 1)
     ExpressionList (children 1)
      Identifier ts
   ExpressionList (children 1)
    Function icebergBucket (children 1)
     ExpressionList (children 2)
      Literal UInt64_13
      Identifier microseconds_since_day_start
