如何仅选择至少具有共同字符的项目

Question

I am trying to figure out how to pull comparative data.

For simplicity sake some fake data is below.

12red34
56red78
90blue23
45blue67
89yellow10

What I want is to pull only items with 3 sequential non defined items.

In this case, it would pull all of the items except 89yellow10 as no other item on the list contains 3 characters in a row that match it. 90blue23 and 45blue67 both contain "blue (or some combination of those letters)" and the same with the "red" items.

This is on a very large table and manually searching using a contain clause doesn't seem feasible.

Thank you.

Answer 1

This will perform with the sample data, however , Laughing Vergil has completely valid points.

Declare @YourTable Table (ID int,SomeString varchar(50))
Insert Into @YourTable values
(1,'12red34'),
(2,'56red78'),
(3,'90blue23'),
(4,'45blue67'),
(5,'89yellow10')


Declare @MatchLen int = 3
;with cte as (
      Select ID,B.*
      From  @YourTable A
      Cross Apply (
                    Select N,S=substring(A.SomeString,N,@MatchLen)
                    From (Select Top (Len(A.SomeString)) N=Row_Number() Over (Order By Number) From master..spt_values) N
                   ) B 
      Where substring(A.SomeString,N,3) like Replicate('[A-Z]',@MatchLen)
)
Select A.*
      ,MinS = min(S)
      ,MaxS = max(S)
 From  @YourTable A
 Join ( 
        Select  S
         From   cte A
         Group  By S
         Having Count(*)>=2
      ) B 
 On  CharIndex(S,SomeString)>0  
 Group By ID,SomeString
 Order By ID

Returns

ID  SomeString  MinS    MaxS
1   12red34     red     red
2   56red78     red     red
3   90blue23    blu     lue
4   45blue67    blu     lue