Question

我有一个查询，当前发现重复，它工作正常。问题是某些记录有一个名为DS的字段，它可以有两个可能的值。 VOTER或DMV。

在查找重复项时，如果找到重复项，我想删除VOTER记录而不是DMV记录。这可以轻松完成吗？

WITH cte
     AS (SELECT *,
                Row_Number() OVER(partition BY fips_county_code, last, suffix, first, birthdate Order by (select null)) AS Rn
         FROM   WORK)
UPDATE cte
SET    DUPES = 'D'
WHERE  RN > 1;

Answer 1

您可以更改order by中的row_number()以包含case表达式，以便'DMV'具有更高优先级，如下所示：

;with cte as (
  select *
    , rn = row_number() over(
        partition by fips_county_code, last, suffix, first, birthdate 
        order by case when ds = 'dmv' then 0 else 1 end asc
        )
  from work
)
update cte
set    dupes = 'D'
where  rn > 1;

Answer 2

将DS放入您的order by子句中。 DMV出现在Voter之前。如果两者都存在，则DVM将是RN 1，选民将是RN 2。

WITH cte
     AS (SELECT *,
                Row_Number() OVER(partition BY fips_county_code, last, suffix, first, birthdate Order by DS ) AS Rn
         FROM   WORK)
UPDATE cte
SET    DUPES = 'D'
WHERE  RN > 1;

如何为数据库中的记录标记设置“优先级”？

2 个答案: