SQL Server 2014

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Microsoft SQL Server 2014 (SP3) (KB4022619) - 12.0.6024.0 (X64) Sep 7 2018 01:37:51 Copyright (c) Microsoft Corporation Express Edition (64-bit) on Windows NT 6.3 <X64> (Build 17763: ) (Hypervisor)

with
  Carrots as (
    select *
    from (
      values
        (cast('2023-09-08 17:00:25.000' as datetime), 17, 0.015),
        ('2023-09-14 03:00:16.000', 3, 10.793),
        ('2023-09-14 04:00:18.000', 4, 10.78),
        ('2023-09-15 16:00:28.000', 16, 0.197),
        ('2023-09-15 17:00:29.000', 17, 10.239)
    ) as C("Date", "Hour", Carrot)
  ),
  Prices as (
    select *
    from (
      values
        ('2023-09-14 00:00:00.000', 0.0176, 0),
         ('2023-09-14 01:00:00.000', 0.0192, 1),
         ('2023-09-14 02:00:00.000', 0.0181, 2),
         ('2023-09-14 03:00:00.000', 0.0177, 3),
         ('2023-09-14 04:00:00.000', 0.0176, 4),
         ('2023-09-14 05:00:00.000', 0.0181, 5),
         ('2023-09-14 06:00:00.000', 0.0199, 6),
         ('2023-09-14 07:00:00.000', 0.0318, 7),
         ('2023-09-14 08:00:00.000', 0.1286, 8),
         ('2023-09-14 09:00:00.000', 0.1257, 9),
         ('2023-09-14 10:00:00.000', 0.1108, 10),
         ('2023-09-14 11:00:00.000', 0.0992, 11),
         ('2023-09-14 12:00:00.000', 0.0663, 12),
         ('2023-09-14 13:00:00.000', 0.034, 13),
         ('2023-09-14 14:00:00.000', 0.0286, 14),
         ('2023-09-14 15:00:00.000', 0.0278, 15),
         ('2023-09-14 16:00:00.000', 0.0268, 16),
         ('2023-09-14 17:00:00.000', 0.0285, 17),
         ('2023-09-14 18:00:00.000', 0.1255, 18),
         ('2023-09-14 19:00:00.000', 0.0555, 19),
         ('2023-09-14 20:00:00.000', 0.0306, 20),
         ('2023-09-14 21:00:00.000', 0.0305, 21),
         ('2023-09-14 22:00:00.000', 0.0273, 22),
         ('2023-09-14 23:00:00.000', 0.0227, 23),
         ('2023-09-15 00:00:00.000', 0.0203, 0),
         ('2023-09-15 01:00:00.000', 0.0051, 1),
         ('2023-09-15 02:00:00.000', 0.0031, 2),
         ('2023-09-15 16:00:00.000', 0.0268, 16),
         ('2023-09-15 17:00:00.000', 0.0285, 17)
    ) as P("Date", Price, "Hour")
  )
select
  c."Date",
  c."Hour",
  c.Carrot,
  p.Price
from Carrots as c
left join Prices as p
  on p."Date" between dateadd(second, -datepart(second, c."Date"), c."Date") and
                      c."Date"
;

Date	Hour	Carrot	Price
2023-09-08 17:00:25.000	17	0.015	null
2023-09-14 03:00:16.000	3	10.793	0.0177
2023-09-14 04:00:18.000	4	10.780	0.0176
2023-09-15 16:00:28.000	16	0.197	0.0268
2023-09-15 17:00:29.000	17	10.239	0.0285