I have a table column that contains values such as abc_1_2_3_4.gif or zzz_12_3_3_45.gif etc.
I want to find the index of each underscore _ in the above values. There will only ever be four underscores but given that they can be in any position in the string, how can I achieve this?
I've tried the substring and charindex function, but I can only reliably get hold of the first one. Any ideas?
220 Answers
You can use the same function inside for the position +1
charindex('_', [TEXT], (charindex('_', [TEXT], 1))+1) in where +1 is the nth time you will want to find.
One way (2k8);
select 'abc_1_2_3_4.gif ' as img into #T insert #T values ('zzz_12_3_3_45.gif') ;with T as ( select 0 as row, charindex('_', img) pos, img from #T union all select pos + 1, charindex('_', img, pos + 1), img from T where pos > 0 ) select img, pos from T where pos > 0 order by img, pos >>>> img pos abc_1_2_3_4.gif 4 abc_1_2_3_4.gif 6 abc_1_2_3_4.gif 8 abc_1_2_3_4.gif 10 zzz_12_3_3_45.gif 4 zzz_12_3_3_45.gif 7 zzz_12_3_3_45.gif 9 zzz_12_3_3_45.gif 11 Update
;with T(img, starts, pos) as ( select img, 1, charindex('_', img) from #t union all select img, pos + 1, charindex('_', img, pos + 1) from t where pos > 0 ) select *, substring(img, starts, case when pos > 0 then pos - starts else len(img) end) token from T order by img, starts >>> img starts pos token abc_1_2_3_4.gif 1 4 abc abc_1_2_3_4.gif 5 6 1 abc_1_2_3_4.gif 7 8 2 abc_1_2_3_4.gif 9 10 3 abc_1_2_3_4.gif 11 0 4.gif zzz_12_3_3_45.gif 1 4 zzz zzz_12_3_3_45.gif 5 7 12 zzz_12_3_3_45.gif 8 9 3 zzz_12_3_3_45.gif 10 11 3 zzz_12_3_3_45.gif 12 0 45.gif You can use the CHARINDEX and specify the starting location:
DECLARE @x VARCHAR(32) = 'MS-SQL-Server'; SELECT STUFF(STUFF(@x,3 , 0, '/'), 8, 0, '/') InsertString ,CHARINDEX('-',LTRIM(RTRIM(@x))) FirstIndexOf ,CHARINDEX('-',LTRIM(RTRIM(@x)), (CHARINDEX('-', LTRIM(RTRIM(@x)) )+1)) SecondIndexOf ,CHARINDEX('-',@x,CHARINDEX('-',@x, (CHARINDEX('-',@x)+1))+1) ThirdIndexOf ,CHARINDEX('-',REVERSE(LTRIM(RTRIM(@x)))) LastIndexOf; GO You can use the following function to split the values by a delimiter. It'll return a table and to find the nth occurrence just make a select on it! Or change it a little for it to return what you need instead of the table.
CREATE FUNCTION dbo.Split ( @RowData nvarchar(2000), @SplitOn nvarchar(5) ) RETURNS @RtnValue table ( Id int identity(1,1), Data nvarchar(100) ) AS BEGIN Declare @Cnt int Set @Cnt = 1 While (Charindex(@SplitOn,@RowData)>0) Begin Insert Into @RtnValue (data) Select Data = ltrim(rtrim(Substring(@RowData,1,Charindex(@SplitOn,@RowData)-1))) Set @RowData = Substring(@RowData,Charindex(@SplitOn,@RowData)+1,len(@RowData)) Set @Cnt = @Cnt + 1 End Insert Into @RtnValue (data) Select Data = ltrim(rtrim(@RowData)) Return END DECLARE @str AS VARCHAR(100) SET @str='1,2 , 3, 4, 5,6' SELECT COALESCE(LTRIM(CAST(('<X>'+REPLACE(@str,',' ,'</X><X>')+'</X>') AS XML).value('(/X)[1]', 'varchar(128)')), ''), COALESCE(LTRIM(CAST(('<X>'+REPLACE(@str,',' ,'</X><X>')+'</X>') AS XML).value('(/X)[2]', 'varchar(128)')), ''), COALESCE(LTRIM(CAST(('<X>'+REPLACE(@str,',' ,'</X><X>')+'</X>') AS XML).value('(/X)[3]', 'varchar(128)')), ''), COALESCE(LTRIM(CAST(('<X>'+REPLACE(@str,',' ,'</X><X>')+'</X>') AS XML).value('(/X)[4]', 'varchar(128)')), ''), COALESCE(LTRIM(CAST(('<X>'+REPLACE(@str,',' ,'</X><X>')+'</X>') AS XML).value('(/X)[5]', 'varchar(128)')), ''), COALESCE(LTRIM(CAST(('<X>'+REPLACE(@str,',' ,'</X><X>')+'</X>') AS XML).value('(/X)[6]', 'varchar(128)')), ''), COALESCE(LTRIM(CAST(('<X>'+REPLACE(@str,',' ,'</X><X>')+'</X>') AS XML).value('(/X)[7]', 'varchar(128)')), ''), COALESCE(LTRIM(CAST(('<X>'+REPLACE(@str,',' ,'</X><X>')+'</X>') AS XML).value('(/X)[8]', 'varchar(128)')), ''), COALESCE(LTRIM(CAST(('<X>'+REPLACE(@str,',' ,'</X><X>')+'</X>') AS XML).value('(/X)[9]', 'varchar(128)')), '') You can look for the four underscore in this way:
create table #test ( t varchar(50) ); insert into #test values ( 'abc_1_2_3_4.gif'), ('zzz_12_3_3_45.gif'); declare @t varchar(50); declare @t_aux varchar(50); declare @t1 int; declare @t2 int; declare @t3 int; declare @t4 int; DECLARE t_cursor CURSOR FOR SELECT t FROM #test OPEN t_cursor FETCH NEXT FROM t_cursor into @t; set @t1 = charindex( '_', @t ) set @t2 = charindex( '_', @t , @t1+1) set @t3 = charindex( '_', @t , @t2+1) set @t4 = charindex( '_', @t , @t3+1) select @t1, @t2, t3, t4 --do a loop to iterate over all table you can test it here.
Or in this simple way:
select charindex( '_', t ) as first, charindex( '_', t, charindex( '_', t ) + 1 ) as second, ... from #test You can try peeling the variable/array, assuming distinctness in your list
declare @array table ----table of values ( id int identity(1,1) ,value nvarchar(max) ) DECLARE @VALUE NVARCHAR(MAX)='val1_val2_val3_val4_val5_val6_val7'----string array DECLARE @CURVAL NVARCHAR(MAX) ---current value DECLARE @DELIM NVARCHAR(1)='_' ---delimiter DECLARE @BREAKPT INT ---current index of the delimiter WHILE EXISTS (SELECT @VALUE) BEGIN SET @BREAKPT=CHARINDEX(@DELIM,@VALUE) ---set the current index --- If @BREAKPT<> 0 ---index at 0 breaks the loop begin SET @CURVAL=SUBSTRING(@VALUE,1,@BREAKPT-1) ---current value set @VALUE=REPLACE(@VALUE,SUBSTRING(@VALUE,1,@BREAKPT),'') ---current value and delimiter, replace insert into @array(value) ---insert data select @CURVAL end else begin SET @CURVAL=@VALUE ---current value now last value insert into @array(value) ---insert data select @CURVAL break ---break loop end end select * from @array ---find nth occurance given the id DECLARE @LEN INT DECLARE @VAR VARCHAR(20) SET @VAR = 'HELLO WORLD' SET @LEN = LEN(@VAR) --SELECT @LEN SELECT PATINDEX('%O%',SUBSTRING(@VAR,PATINDEX('%O%' ,@VAR) + 1 ,PATINDEX('%O%',@VAR) + 1)) + PATINDEX('%O%',@VAR) My SQL supports the function of a substring_Index where it will return the postion of a value in a string for the n occurance. A similar User defined function could be written to achieve this. Example in the link
Alternatively you could use charindex function call it x times to report the location of each _ given a starting postion +1 of the previously found instance. until a 0 is found
Edit: NM Charindex is the correct function
1I did this creating several separate custom functions, one for each position of the searched character i.e. 2nd, 3rd:
CREATE FUNCTION [dbo].[fnCHARPOS2] (@SEARCHCHAR VARCHAR(255), @SEARCHSTRING VARCHAR(255)) RETURNS INT AS BEGIN RETURN CHARINDEX(@SEARCHCHAR,@SEARCHSTRING(CHARINDEX(@SEARCHCHAR,@SEARCHSTRING,0)+1));
CREATE FUNCTION [dbo].[fnCHARPOS3] (@SEARCHCHAR VARCHAR(255), @SEARCHSTRING VARCHAR(255)) RETURNS INT AS BEGIN RETURN CHARINDEX(@SEARCHCHAR,@SEARCHSTRING, (CHARINDEX(@SEARCHCHAR,@SEARCHSTRING, (CHARINDEX(@SEARCHCHAR,@SEARCHSTRING,0)+1)))+1); You can then pass in as a parameter the character you are searching for and the string you are searching in:
So if you were searching for 'f' and wanted to know position of 1st 3 occurences:
select database.dbo.fnCHARPOS2('f',tablename.columnname), database.dbo.fnCHARPOS3('f',tablename.columnname) from tablename It worked for me!
I decided to use a recursive function because for me it was easier to follow the logic. Note that SQL Server has a default function recursion limit of 32, so this is only good for smaller workloads.
create function dbo._charindex_nth ( @FindThis varchar(8000), @InThis varchar(max), @StartFrom int, @NthOccurence tinyint ) returns bigint as begin /* Recursive helper used by dbo.charindex_nth to return the position of the nth occurance of @FindThis in @InThis Who When What PJR 160421 Initial */ declare @Pos bigint if isnull(@NthOccurence, 0) <= 0 or isnull(@StartFrom, 0) <= 0 begin select @Pos = 0 end else begin if @NthOccurence = 1 begin select @Pos = charindex(@FindThis, @InThis, @StartFrom) end else begin select @Pos = dbo._charindex_nth(@FindThis, @InThis, nullif(charindex(@FindThis, @InThis, @StartFrom), 0) + 1, @NthOccurence - 1) end end return @Pos end create function dbo.charindex_nth ( @FindThis varchar(8000), @InThis varchar(max), @NthOccurence tinyint ) returns bigint as begin /* Returns the position of the nth occurance of @FindThis in @InThis Who When What PJR 160421 Initial */ return dbo._charindex_nth(@FindThis, @InThis, 1, @NthOccurence) end declare @val varchar(max) = 'zzz_12_3_3_45.gif' select dbo.charindex_nth('_', @val, 1) Underscore1 , dbo.charindex_nth('_', @val, 2) Underscore2 , dbo.charindex_nth('_', @val, 3) Underscore3 , dbo.charindex_nth('_', @val, 4) Underscore4 DECLARE @T AS TABLE(pic_name VARCHAR(100)); INSERT INTO @T VALUES ('abc_1_2_3_4.gif'),('zzz_12_3_3_45.gif'); SELECT A.pic_name, P1.D, P2.D, P3.D, P4.D FROM @T A CROSS APPLY (SELECT NULLIF(CHARINDEX('_', A.pic_name),0) AS D) P1 CROSS APPLY (SELECT NULLIF(CHARINDEX('_', A.pic_name, P1.D+1), 0) AS D) P2 CROSS APPLY (SELECT NULLIF(CHARINDEX('_', A.pic_name, P2.D+1),0) AS D) P3 CROSS APPLY (SELECT NULLIF(CHARINDEX('_', A.pic_name, P3.D+1),0) AS D) P4 I've used a function to grab the "nth" element from a delimited string field with great success. Like mentioned above, it's not a "fast" way of dealing with things but it sure as heck is convenient.
create function GetArrayIndex(@delimited nvarchar(max), @index int, @delimiter nvarchar(100) = ',') returns nvarchar(max) as begin declare @xml xml, @result nvarchar(max) set @xml = N'<root><r>' + replace(@delimited, @delimiter,'</r><r>') + '</r></root>' select @result = r.value('.','varchar(max)') from @xml.nodes('//root/r[sql:variable("@index")]') as records(r) return @result end A simple sample to do this with xml conversion:
SELECT 'A|B|C' , concat('<x>', REPLACE('A|B|C', '|', '</x><x>'), '</x>') , cast(concat('<x>', REPLACE('A|B|C', '|', '</x><x>'), '</x>') as xml).query('/x[2]') , cast(concat('<x>', REPLACE('A|B|C', '|', '</x><x>'), '</x>') as xml).value('/x[2]', 'varchar'); And here a translation for your sample:
SELECT gifname ,cast(concat('<x>', REPLACE(gifname, '_', '</x><x>'), '</x>') as xml).query('/x[2]') as xmlelement , cast(concat('<x>', REPLACE(gifname, '_', '</x><x>'), '</x>') as xml).value('/x[2]', 'varchar(10)') as result FROM ( SELECT 'abc_1_2_3_4.gif' as gifname UNION ALL SELECT 'zzz_12_3_3_45.gif' ) tmp I was toying with a faster way to do this than simply iterating through the string.
CREATE FUNCTION [ssf_GetNthSeparatorPosition] ( @TargetString VARCHAR(MAX) , @Sep VARCHAR(25) , @n INTEGER ) RETURNS INTEGER /**************************************************************************************** --############################################################################# -- Returns the position of the Nth Charactor sequence -- 1234567890123456789 -- Declare @thatString varchar(max) = 'hi,there,jay,yo' Select dbo.ssf_GetNthSeparatorPosition(@thatString, ',', 3) --would return 13 --############################################################################ ****************************************************************************************/ AS BEGIN DECLARE @Retval INTEGER = 0 DECLARE @CurPos INTEGER = 0 DECLARE @LenSep INTEGER = LEN(@Sep) SELECT @CurPos = CHARINDEX(@Sep, @TargetString) IF ISNULL(@LenSep, 0) > 0 AND @CurPos > 0 BEGIN SELECT @CurPos = 0 ;with lv0 AS (SELECT 0 g UNION ALL SELECT 0) ,lv1 AS (SELECT 0 g FROM lv0 a CROSS JOIN lv0 b) -- 4 ,lv2 AS (SELECT 0 g FROM lv1 a CROSS JOIN lv1 b) -- 16 ,lv3 AS (SELECT 0 g FROM lv2 a CROSS JOIN lv2 b) -- 256 ,lv4 AS (SELECT 0 g FROM lv3 a CROSS JOIN lv3 b) -- 65,536 ,lv5 AS (SELECT 0 g FROM lv4 a CROSS JOIN lv4 b) -- 4,294,967,296 ,Tally (n) AS (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM lv5), results AS ( SELECT n - LEN(@Sep) AS Nth , row_number() OVER ( ORDER BY n ) - 1 AS Position FROM Tally t WHERE n BETWEEN 1 AND DATALENGTH(@TargetString) + DATALENGTH(@Sep) AND SUBSTRING(@Sep + @TargetString, n, LEN(@Sep)) = @Sep) SELECT @CurPos = Nth FROM results WHERE results.Position = @n END RETURN @CurPos END GO declare @a nvarchar(50)='Enter Your string ' declare @character char='e' declare @nthoccurence int = 2 declare @i int = 1 declare @j int =0 declare @count int = len(@a)-len(replace(@a,@character,'')) if(@count >= @nthoccurence) begin while (@I <= @nthoccurence) begin set @j= CHARINDEX(@character,@a,@j+1) set @i= @i+1 end print @j end else Print 'you have only '+convert(nvarchar ,@count)+' occurrences of '+@character end DECLARE @x VARCHAR(32) = 'MS-SQL-Server'; SELECT SUBSTRING(@x,0,CHARINDEX('-',LTRIM(RTRIM(@x)))) A, SUBSTRING(@x,CHARINDEX('-',LTRIM(RTRIM(@x)))+1,CHARINDEX('-' ,LTRIM(RTRIM(@x)))) B, SUBSTRING(@x,CHARINDEX('-',REVERSE(LTRIM(RTRIM(@x))))+1,LEN(@x)-1) C A B C MS SQL Server Inspired by Alex K's reply One way (2k8), I have created a script for a Token Function for the SQL Server for returning a specific token from a string. I needed this for refacturing a SSIS-package to T-SQL without having to implement Alex' solution a number of times manually. My function has one disadvantage: It returns the token value as a table (one column, one row) instead of as a varchar value. If anyone has a solution for this, please let me know.
DROP FUNCTION [RDW].[token] GO create function [RDW].[token] (@string varchar(8000), @split varchar(50), @returnIndex int) returns table as return with T(img, starts, pos, [index]) as ( select @string, 1, charindex(@split, @string), 0 union all select @string, pos + 1, charindex(@split, @string, pos + 1), [index]+1 from t where pos > 0 ) select substring(img, starts, case when pos > 0 then pos - starts else len(img) end) token from T where [index] = @returnIndex GO Try this
CREATE FUNCTION [dbo].[CHARINDEX2] ( @expressionToFind VARCHAR(MAX), @expressionToSearch VARCHAR(MAX), @occurrenceIndex INT, @startLocation INT = 0 ) RETURNS INT AS BEGIN IF @occurrenceIndex < 1 BEGIN RETURN CAST('The argument @occurrenceIndex must be a positive integer.' AS INT) END IF @startLocation < 0 BEGIN RETURN CAST('The argument @startLocation must be a non negative integer.' AS INT) END DECLARE @returnIndex INT SET @returnIndex = CHARINDEX(@expressionToFind, @expressionToSearch, @startLocation) IF (@occurrenceIndex = 1) BEGIN RETURN @returnIndex END DECLARE @target_length INT SET @target_length = LEN(@expressionToFind) SET @occurrenceIndex += -1 WHILE (@occurrenceIndex > 0 AND @returnIndex > 0) BEGIN SET @returnIndex = CHARINDEX(@expressionToFind, @expressionToSearch, @returnIndex + @target_length); SET @occurrenceIndex += -1 END RETURN @returnIndex END GO I use this function:
CREATE FUNCTION [pub].[SplitString] ( @StringToSplit nvarchar(MAX), @Delimiter as nvarchar(10) ) -- Example of use: -- select * from [pub].[SplitString] ('one;two;three;;for & six;', ';') RETURNS @returnList TABLE ([Item] [nvarchar] (4000), [ID] [int] IDENTITY(1,1)) AS BEGIN DECLARE @xml as xml SET @xml = cast ( ('<X>' + replace(replace(@StringToSplit, @Delimiter ,'</X><X>'),'&','&') + '</X>' ) as xml ) INSERT INTO @returnList([Item]) SELECT N.value('.', 'nvarchar(max)') as [Item] FROM @xml.nodes('X') as T(N) RETURN END 
