Question

我有一个包含3个字段的数据列表，ISIN，CompanyId和EffectiveDate。 ISIN在CompanyId和生效日期都重复。

示例数据：

SELECT ISIN, CompanyId, MAX(EffectiveDate)
FROM [MappingData].[dbo].[ESGMappingISIN]
GROUP BY ISIN,CompanyId

使用

ISIN            CompanyId    EffectiveDate
AED001410045    58105545     2012-02-09
AEDFXA1G39P8    132844116    2017-09-21
ARDEUT110020    249603       2012-02-09
ARDEUT110020    416264458    2017-03-22

我可以删除ISIN和CompanyId上的重复项以返回

A) Return ISIN and CompanyId where ISIN is distinct
B) If 1 ISIN has 2 CompanyIds, return the line with the later effective date.

我需要的最后一步是：

ISIN            CompanyId    EffectiveDate
AED001410045    58105545     2012-02-09
AEDFXA1G39P8    132844116    2017-09-21
ARDEUT110020    416264458    2017-03-22

理想输出

{{1}}

Answer 1

您可以使用row_number()：

SELECT *
FROM (SELECT ISIN, CompanyId, MAX(EffectiveDate) as maxed,
             ROW_NUMBER() OVER (PARTITION BY ISIN ORDER BY MAX(Effectivedate) DESC) as seqnum
      FROM [MappingData].[dbo].[ESGMappingISIN]
      GROUP BY ISIN, CompanyId
     ) m
WHERE seqnum = 1;

Answer 2

你可以使用这样的子查询：

SELECT
   B.ISIN,
   B.CompanyID,
   B.EffectiveDate 
FROM
   (
      SELECT
         ISIN,
         CompanyId,
         MAX(EffectiveDate) AS EffectiveDate 
      FROM
         ESGMappingISIN 
      GROUP BY
         ISIN,
         CompanyId 
   )
   AS B 
   JOIN
      (
         SELECT
            ISIN,
            MAX(EffectiveDate) AS EffectiveDate 
         FROM
            ESGMappingISIN
         GROUP BY ISIN 
      ) AS A 
      ON B.ISIN = A.ISIN 
      AND B.EffectiveDate = A.EffectiveDate

字段1在字段2上重复，需要根据字段3选择1，并返回字段1和2

2 个答案: