Question

我的ID字符串在数据库中具有这些值，如下所示：

My_ID_String
=============
ABC123
123
ABC456
798

我的最终目标是替换所有没有前缀的ABC。但是我遇到的挑战是该列必须具有唯一值。我有解决这个问题的计划。但是，我要完成的工作是，如果我删除前缀不适当，则找出具有重复项的重复项。换句话说，我希望查询返回ABC456的结果，但不返回ABC123的结果，因为如果执行替换功能，这将导致重复。

预期结果：

My_ID_String
============
ABC456

Answer 1

另一个选择

示例

;with cte as (
Select Top 1 with ties *
 From  YourTable
 Order By sum(1) over (partition by replace(My_ID_String,'ABC','') )
)
Select * 
 From  cte 
 Where My_ID_String like 'ABC%'

返回

My_ID_String
ABC456

Answer 2

您可以使用：

SELECT My_Id_String  AS MyIdString
FROM tab
WHERE My_Id_String LIKE 'ABC%'
EXCEPT
SELECT 'ABC' + My_Id_String
FROM tab
WHERE My_Id_String NOT LIKE 'ABC%'

db<>fiddle demo

Answer 3

那是你想做什么

WITH StrTable AS
(
SELECT 'ABC123' My_ID_String
UNION 
SELECT '12355555'
UNION
SELECT 'ABC456'
UNION
SELECT NULL
UNION
SELECT 'DEF123'
UNION
SELECT 'DEF456'
UNION
SELECT 'GHI123'
UNION
SELECT 'GHI456'
UNION
SELECT 'GHI789'
)
SELECT CONCAT( LEFT(My_ID_String, 3),
               MAX(REPLACE(My_ID_String, LEFT(My_ID_String, 3), ''))
             ) Result
FROM StrTable
WHERE TRY_CAST(LEFT(My_ID_String, 3) AS INT) IS NULL
      AND My_ID_String IS NOT NULL
GROUP BY LEFT(My_ID_String, 3);

返回：

+--------+
| Result |
+--------+
| ABC456 |
| DEF456 |
| GHI789 |
+--------+

Demo

Answer 4

由于这似乎是最终目标，因此可以在一个步骤中完成所有这两个操作，从而获得所有不同的值。消除重复项时，只需获取所需的独特值即可。您可能正在寻找类似这样的东西。

declare @Something table
(
    My_ID_String varchar(50)
)
insert @Something values
('ABC123')
, ('123')
, ('ABC456')
, ('798')

select case when count(replace(s.My_ID_String, 'ABC', '')) = 1 then max(s.My_ID_String) else max(replace(s.My_ID_String, 'ABC', '')) end
from @Something s
group by replace(s.My_ID_String, 'ABC', '')

如何在前缀和非前缀值中找到重复的值？

4 个答案: