如何获取 sql 中的每 n 行值

Question

I have a select statement in sql:

SELECT DISTINCT [Year] FROM [data_list] ORDER BY [YEAR] ASC;

Result:

Year
----
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028

I want list of year in 3 increments. For example:

Year
----
2019
2022
2025
2028

Answer 1

One way to do it is to use a common table expression with dense_rank, and then filter the results by it.

First, create and populate sample table ( Please save us this step in your future questions):

DECLARE @T AS TABLE
(
    [Year] int
)

INSERT INTO @T ([Year]) VALUES
(2019),
(2019),
(2019),
(2020),
(2020),
(2021),
(2022),
(2022),
(2023),
(2024),
(2024),
(2025),
(2025),
(2026),
(2027),
(2027),
(2028);

The cte and query:

WITH CTE AS
(
    SELECT [Year],
            DENSE_RANK() OVER(ORDER BY [Year]) - 1 As dr
    FROM @T
)

SELECT DISTINCT [Year]
FROM CTE
WHERE dr % 3 = 0
ORDER BY [Year]

results:

Year
2019
2022
2025
2028

Answer 2

You can use ROW_NUMBER :

SELECT [Year] 
FROM (
  SELECT [Year], ROW_NUMBER() OVER (ORDER BY [Year] ASC) rn 
  FROM table_name
  GROUP BY [YEAR]
) t WHERE (t.rn - 1) % 3 = 0

demo on dbfiddle.uk

Answer 3

Try it,

;WITH CTEs AS 
(
    SELECT *,(CASE WHEN [Year] %3 =0 THEN [Year] END) AS [Year] FROM yourTable
)
SELECT * FROM CTEs WHERE [Year] IS NOT NULL