sql-server - SQL查询获取每分钟的最后一条记录

Question

我有一个表格，每秒更新一些值。我想检索每分钟的最后一条记录。

我试过这段代码，但它返回了所有记录。

SELECT 
    t0.brandID, t0.brandName, t0.cdt, t0.udt, t0.brandstatus  
FROM 
    brands t0 
WHERE  
    t0.cdt BETWEEN '2013-11-15' and '2014-11-15' 
GROUP BY 
    t0.brandID, t0.brandName, t0.cdt, t0.udt, t0.brandstatus,(datepart(minute, t0.cdt) / 1)

我的表结构是:

ID  brandname     cdt                          udt  brandstatus addedby
1   khasim  2013-11-01 19:14:18.120 2013-11-15 19:14:18.123 1   1
2   khasim  2013-11-01 19:14:18.121 2013-11-15 19:14:18.123 1   1
3   khasim  2013-11-01 19:14:18.122 2013-11-15 19:14:18.123 1   1          
4   khasim  2013-11-01 19:14:18.123 2013-11-15 19:14:18.123 1   1
5   khasim  2013-11-02 19:17:57.700 2013-11-15 19:17:57.700 1   2
6   tanveer 2013-11-03 19:18:05.947 2013-11-15 19:18:05.947 1   2
7   abcdef  2013-11-04 20:50:06.783 2013-11-15 20:50:06.787 1   4

预期结果是:

 ID  brandname     cdt                          udt  brandstatus addedby

    4   khasim  2013-11-01 19:14:18.123 2013-11-15 19:14:18.123 1   1
    5   khasim  2013-11-02 19:17:57.700 2013-11-15 19:17:57.700 1   2
    6   tanveer 2013-11-03 19:18:05.947 2013-11-15 19:18:05.947 1   2
    7   abcdef  2013-11-04 20:50:06.783 2013-11-15 20:50:06.787 1   4

Answer 1

您可以使用以下查询:

SELECT ID, brandname, cdt, udt, brandstatus, addedby
FROM (
  SELECT ID, brandname, cdt, udt, brandstatus, addedby,
         ROW_NUMBER() OVER (PARTITION BY brandname, 
                                         CAST(udt AS DATE),
                                         CONVERT(VARCHAR(5), udt, 114) 
                            ORDER BY udt DESC) AS rn
  FROM brands) AS t
WHERE t.rn = 1

这部分:

CONVERT(VARCHAR(5), udt, 114)

用于从 udt 字段中提取小时和分钟。