Is there a LastIndexOf in SQL Server?

Problem

I am trying to parse out a value from a string that involves getting the last index of a string. Currently, I am doing a horrible hack that involves reversing a string:

SELECT REVERSE(SUBSTRING(REVERSE(DB_NAME()), 1, 
    CHARINDEX('_', REVERSE(DB_NAME()), 1) - 1))

This code is nearly unreadable to me. I recently upgraded to SQL Server 2016 and am expecting for a better solution. Is there any?

Asked by AngryHacker

Solution #1

Use: if you want everything after the final .

select right(db_name(), charindex('_', reverse(db_name()) + '_') - 1)

If you want to go back in time, use left():

select left(db_name(), len(db_name()) - charindex('_', reverse(db_name()) + '_'))

Answered by Gordon Linoff

Solution #2

I wrote two methods, one of which returns the selected character’s LastIndexOf.

CREATE FUNCTION dbo.LastIndexOf(@source nvarchar(80), @pattern char)
RETURNS int
BEGIN  
       RETURN (LEN(@source)) -  CHARINDEX(@pattern, REVERSE(@source)) 
END;  
GO

and 1 to get a string that comes before this LastIndexOf. Perhaps it will be of use to someone.

CREATE FUNCTION dbo.StringBeforeLastIndex(@source nvarchar(80), @pattern char)
RETURNS nvarchar(80)
BEGIN  
       DECLARE @lastIndex int
       SET @lastIndex = (LEN(@source)) -  CHARINDEX(@pattern, REVERSE(@source)) 

     RETURN SUBSTRING(@source, 0, @lastindex + 1) 
     -- +1 because index starts at 0, but length at 1, so to get up to 11th index, we need LENGTH 11+1=12
END;  
GO

Answered by user2771704

Solution #3

LastIndexOf is not available in SQL Server.

These are the string functions that are available.

You can, however, always construct your own function.

CREATE FUNCTION dbo.LastIndexOf(@source text, @pattern char)  
RETURNS 
AS       
BEGIN  
    DECLARE @ret text;  
    SELECT into @ret
           REVERSE(SUBSTRING(REVERSE(@source), 1, 
           CHARINDEX(@pattern, REVERSE(@source), 1) - 1))
    RETURN @ret;  
END;  
GO 

Answered by Juan Carlos Oropeza

Solution #4

You can do it in a set-based fashion like this once you have one of the split strings from here.

declare @string varchar(max)
set @string='C:\Program Files\Microsoft SQL Server\MSSQL\DATA\AdventureWorks_Data.mdf'

;with cte
as
(select *,row_number() over (order by (select null)) as rownum
from [dbo].[SplitStrings_Numbers](@string,'\')
)
select top 1 item from cte order by rownum desc

**Output:**  
AdventureWorks_Data.mdf

Answered by TheGameiswar

Solution #5

CREATE FUNCTION dbo.LastIndexOf(@text NTEXT, @delimiter NTEXT)  
RETURNS INT
AS       
BEGIN  
  IF (@text IS NULL) RETURN NULL;
  IF (@delimiter IS NULL) RETURN NULL;
  DECLARE @Text2 AS NVARCHAR(MAX) = @text;
  DECLARE @Delimiter2 AS NVARCHAR(MAX) = @delimiter;
  DECLARE @Index AS INT = CHARINDEX(REVERSE(@Delimiter2), REVERSE(@Text2));
  IF (@Index < 1) RETURN 0;
  DECLARE @ContentLength AS INT = (LEN('|' + @Text2 + '|') - 2);
  DECLARE @DelimiterLength AS INT = (LEN('|' + @Delimiter2 + '|') - 2);
  DECLARE @Result AS INT = (@ContentLength - @Index - @DelimiterLength + 2);
  RETURN @Result;
END

Answered by Christoph

Post is based on https://stackoverflow.com/questions/39002025/is-there-a-lastindexof-in-sql-server