Remove leading zero in a temp variable - sql-server

I have declalared a temp variable in sql. it contains a string A001, A011, A002, A14, A158.
i want to remove zeroes to get following output
A1, A2, A11, A14, A158


You can achieve what you're after with some string manipulation.
So if you take the first character from A010:
DECLARE #SomeValue nvarchar(10) = 'A010'
SELECT LEFT(#SomeValue, 1) -- gives you 'A'
Then get the numeric part, by removing the first character and convert it to an integer:
SELECT CONVERT(INT, SUBSTRING(#SomeValue, 2, LEN(#SomeValue) - 1)) -- returns 10
This will remove the leading zeroes for you. You then just need to convert it back to a string and append it on to the first character.
Full working solution:
DECLARE #T1 TABLE ( SomeValue NVARCHAR(10) )
INSERT INTO #T1
( SomeValue )
VALUES ( 'A001' ),
( 'A011' ),
( 'A002' ),
( 'A14' ),
( 'A158' ),
( 'A010' )
SELECT SomeValue AS Original ,
LEFT(SomeValue, 1)
+ CONVERT(NVARCHAR(10),
CONVERT(INT, SUBSTRING(SomeValue, 2, LEN(SomeValue)-1))) RemoveLeadingZeroes
FROM #T1


Use this: (I used XML to replace extract each word and then replaced the 0's by casting 0010 to 10 and combined the values A + 10 to get A10 and again combined the each word to form A1, A2, A14..)
DECLARE #string VARCHAR(MAX),
#Split CHAR(1),
#X xml
SELECT #string = 'A001, A011, A002, A14, A158',
#Split = ', '
SELECT #X = CONVERT(xml,'<root><s>' + REPLACE(#string,#Split,'</s><s>') + '</s></root>')
SELECT
STUFF(((SELECT ', ' + CAST(Result AS VARCHAR(100)) FROM
(SELECT SUBSTRING(LTRIM(Result), 1, 1) +
CAST(CAST(SUBSTRING(LTRIM(Result), 2, LEN(LTRIM(Result))) AS INT) AS VARCHAR) AS Result
FROM
(SELECT T.c.value('.','varchar(max)') AS Result
FROM #X.nodes('/root/s') T(c)) AS NewResult)
AS NewResult1
FOR xml path(''), type).value('.','varchar(max)')), 1,2,'')
AS FinalResult
SqlFiddle: Demo

Related

Remove all Non-Numeric Chars from String

I would like to truncate all characters in a column, no matter where they are.
Example:
"+49123/4567890(testnumber)"
Should be changed to
"491234567890"
Is there a way without doing a replace for each char?
I have tried to replace it with several, but it is very time-consuming.

As you mentioned, if you are expecting only [a-zA-z()/+], you can use the translate function which is available from 2017+
declare #table TABLE (str varchar(max))
insert into #table
select '+49123/4567890(estnumber)'
select replace(translate(str, '/+()abcdefghijklmnopqrstuvwxyz', '~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~'), '~', '') digits
from #table
For more complex scenarios where the characters are not known, you can try using recursive CTE on a string column to extract only digits like following query.
;with cte
as (
select v.txt originalstring
,v.txt
,convert(varchar(max), '') as digits
,1 as lev
from (
values ('+49123/4567890(testnumber)')
,('+234&*#$%!##')
) v(txt)
union all
select originalstring
,stuff(txt, 1, 1, '')
,(
case
when left(txt, 1) LIKE '[0-9]'
then digits + left(txt, 1)
else digits
end
)
,lev + 1
from cte
where txt > ''
)
select originalstring
,digits
from (
select c.originalstring
,c.digits
,row_number() over (partition by c.originalstring order by lev desc
) rn
from cte c
) t
where rn = 1
Output
originalstring digits
--------------- --------
+234&*#$%!## 234
+49123/4567890(testnumber) 491234567890

A set-based option that exists in SQL Server 2017+ is to utilise translate.
You can hopefully adapt the following to your specific use-case:
select col, Replace(Translate(col, r, Replicate('*', Len(r))), '*', '') Newcol
from t
cross apply(values(' ABCDEFGHIJKLMNOPQRSTUVWXYZ/\+()'))r(r);
Example DB<>Fiddle

Instead of hardcoding the list of "bad" characters you can use a double TRANSLATE to first get the unwanted characters and then plug that back into TRANSLATE.
DECLARE #table TABLE
(
str VARCHAR(max)
)
INSERT INTO #table
SELECT '+49123/4567890(testnumber) '
DECLARE #CharactersToKeep VARCHAR(30) = '0123456789'
SELECT REPLACE(TRANSLATE(str, bad_chars, REPLICATE('X', LEN(bad_chars + 'X') - 1)), 'X', '')
FROM #table
CROSS APPLY (SELECT REPLACE(TRANSLATE(str, #CharactersToKeep, REPLICATE(LEFT(#CharactersToKeep, 1), LEN(#CharactersToKeep))), LEFT(#CharactersToKeep, 1), '')) ca(bad_chars)

Replacing Part of a String without Replace/Stuff

This is my string: 11.0000.0101.000.000.0101.000.000
I need to replace ONLY the first "0101" with "101." I can't use replace, as it replaces the 2nd instance of 0101 as well.
I tried
stuff(string, 9, 3, '101')
but since the replacement string is shorter than the existing string, I end up with
11.0000.1011.000.000.0101.000.000
What can I use besides REPLACE or STUFF? Thanks!

declare #t table(s varchar(100))
insert into #t values
( '11.0000.0101.000.000.0101.000.000'), ('abc');
select case charindex('0101', s)
when 0 then s
else stuff(s, charindex('0101', s), 4, '101')
end as new_s
from #t;

Your expression was almost right.
Just tell it to replace 4 characters of the original string instead of 3 :
stuff(string, 9, 4, '101')
But this will only work if your string has always the same positions.

you can do something like:
replace (stuff(string,9,3,'#101'),'#','')

If you need replace all 0101 to 101 go with below code
DECLARE #TempData TABLE(Data VARCHAR(1000));
INSERT INTO #TempData VALUES
('11.0000.0101.000.000.0101.000.000');
;WITH Cte
AS (
SELECT CASE
WHEN DATA = '0101'
THEN '101'
ELSE CAST(DATA AS VARCHAR(10))
END AS DATA
FROM (
SELECT Split.a.value('.', 'VARCHAR(1000)') AS Data
FROM (
SELECT CAST('<S>' + REPLACE(Data, '.', '</S><S>') + '</S>' AS XML) AS Data
FROM #TempData
) AS A
CROSS APPLY Data.nodes('/S') AS Split(a)
) Dt
)
SELECT STUFF((
SELECT '.' + DATA
FROM cte
FOR XML PATH('')
), 1, 1, '') AS ExpectedResult
OutPut
ExpectedResult
11.0000.101.000.000.101.000.000

Yet another option if you don't know the 1st observation
Declare #S varchar(50) = '11.0000.0101.000.000.0101.000.000'
Declare #Find varchar(25) = '0101'
Declare #Repl varchar(25) = '101'
Select isnull(stuff(#S, charindex(#Find,#S), len(#Find), #Repl),#S)
Returns
11.0000.101.000.000.0101.000.000

subquery with table value function not working

DECLARE #temp AS TABLE (id INT, NAME VARCHAR(20) )
DECLARE #str VARCHAR(20) = '1,2'
INSERT INTO #temp (id, NAME)
VALUES (1, ''), (2, ''), (2, '')
SELECT *
FROM #temp a
WHERE id IN ((SELECT String FROM dbo.FN_SplitStrings(#str,',')))
I'm getting the following error while running this
Conversion failed when converting the varchar value '1,2' to data type
int.
Code:
CREATE function [dbo].[FN_SplitStrings]
(
#StringToSplit varchar(8000),
#Separator varchar(128)
)
RETURN TABLE
AS
RETURN
with indices as
(
select
0 S, 1 E
union all
select
E, charindex(#Separator, #StringToSplit, E) + len(#Separator)
from
indices
where E > S
)
select
substring(#StringToSplit,S, case when E > len(#Separator)
then e-s-len(#Separator) else len(#StringToSplit) - s + 1 end) String ,
S StartIndex
from
indices
where
S > 0

Try this. This splitting can be used without a function
DECLARE #temp AS TABLE
(
id INT,
NAME VARCHAR(20)
)
DECLARE #str VARCHAR(20)='1,2'
INSERT INTO #temp
( id, NAME )
VALUES ( 1, '' ),
( 2, ''),
( 2, '')
SELECT * FROM #temp a
WHERE id IN
(
SELECT LTRIM(RTRIM(Split.a.value('.', 'VARCHAR(100)'))) 'KeyWords'
FROM
(
-- To change ',' to any other delimeter, just change ',' before '</M><M>' to your desired one
SELECT CAST ('<M>' + REPLACE(#str, ',', '</M><M>') + '</M>' AS XML) AS Data
) AS A
CROSS APPLY Data.nodes ('/M') AS Split(a)
)
Click here to view the result
EDIT:
You had some problems in function for splitting.
Function
ALTER FUNCTION dbo.FN_SplitStrings(#StringToSplit varchar(8000),#Separator char(1))
RETURNS table
AS
RETURN (
WITH splitter_cte AS (
SELECT CHARINDEX(#Separator, #StringToSplit) as pos, 0 as lastPos
UNION ALL
SELECT CHARINDEX(#Separator, #StringToSplit, pos + 1), pos
FROM splitter_cte
WHERE pos > 0
)
SELECT SUBSTRING(#StringToSplit, lastPos + 1,
case when pos = 0 then 80000
else pos - lastPos -1 end) as String
FROM splitter_cte
)
Query
DECLARE #temp AS TABLE (id INT, NAME VARCHAR(20) )
DECLARE #str VARCHAR(20) = '1,2'
INSERT INTO #temp (id, NAME)
VALUES (1, ''), (2, ''), (2, '')
SELECT *
FROM #temp a
WHERE id IN ((SELECT String FROM dbo.FN_SplitStrings(#str,',')))
Click here to view result

The reason is a mix in data types and the fact that your function is an inline table valued functions which means that it is embedded into the query before query optimization takes place.
If you remove where S > 0 from your function and execute it with 1,2, the result of the function is:
String
------
1,2
1
2
Notice the first row where the value is 1,2.
When the optimizer does its job with your query the comparison against the column id is done before the where clause of the function is evaluated. In that comparison you have an implicit cast to int and 1,2 can not be casted to an int.
To fix this you can make sure that the String column of your split function is always an int (and perhaps changing the name of the column in the process).
select
cast(substring(#StringToSplit,S, case when E > len(#Separator)
then e-s-len(#Separator)
else len(#StringToSplit) - s + 1
end) as int) String ,

Finding a word after specific string - sql management studio 2012

I have a text column with fields as per below (small sample, there are many variations):
INSERT INTO #retention1 VALUES ('hello Action=Refer non-action=non-refer')
INSERT INTO #retention1 VALUES ('bye Action=Follow non-action=non-refer')
INSERT INTO #retention1 VALUES ('hello non-action=non-refer Action=compare')
I need to find the word after "Action="
example ANSWER :
Entry 1: Refer
Entry 2: Follow
Entry 3: Compare
If all the words after "Action=" was the same length then I am able to do it. Unfortunately the length is unknown of all variations. The word after action is almost always different not only the 3 variations above.
Any ideas suggestions would be highly appreciated.
This is the code I used for the "Refer" example only which works:
BEGIN
DECLARE #P_string nvarchar (100),
#P_variable nvarchar (100)/*,
#P_return_null nvarchar(100) = 'Y'*/
set #p_string = 'hello Action=Refer non-action=non-refer'
set #p_variable = 'Action'
select substring(#p_string, charindex(upper(#P_variable),upper(#P_string)) +len(#p_variable)+1,5) as trying
END;

Try this:
BEGIN
DECLARE #ret nvarchar (100),#P_string nvarchar (100),
#P_variable nvarchar (100)/*,
#P_return_null nvarchar(100) = 'Y'*/
set #p_string = 'hello Action=Refer non-action=non-refer'
set #p_variable = 'Action'
select #ret=substring(#p_string, charindex(upper(#P_variable),upper(#P_string)) +len(#p_variable)+1,100)
select substring(#ret,0,charindex(' ',lower(#ret),0))
END;

The code you are looking for should first look for the string Action and then for a space character after that word. After that you have all you need to manipulate your source string.
This should work:
DECLARE
#P_string nvarchar (100),
#P_variable nvarchar (100),
#idx1 int,
#idx2 int
SET #p_string = 'hello Action=Refer non-action=non-refer'
SET #p_variable = 'Action'
SELECT
#idx1 = charindex(lower(#P_variable),lower(#P_string)) + len(#p_variable) + 1,
#idx2 = charindex(lower(' '), #P_string, #idx1)
SELECT #idx1, #idx2
SELECT SUBSTRING(
#p_string,
#idx1,
#idx2 - #idx1) as trying
EDIT
After more thoroughly reviewing the requirements, I decided to tailor a rCTE structure that I use for similar purposes. Here it goes.
CREATE TABLE #retention1 (
ID int,
txt nvarchar (100)
)
INSERT INTO #retention1 VALUES (1, 'hello Action=Refer non-action=non-refer')
INSERT INTO #retention1 VALUES (2, 'bye Action=Follow non-action=non-refer')
INSERT INTO #retention1 VALUES (3, 'hello non-action=non-refer Action=compare')
;WITH T AS (
SELECT
ID,
Row = 0,
StartIdx = CAST(0 as int),
EndIdx = CAST(0 as int),
Result = CAST('' as nvarchar(max))
FROM #retention1
UNION ALL
SELECT
r1.ID,
Row + 1,
StartIdx = CAST(newstartidx AS int),
EndIdx = CAST(EndIdx + newendidx as int),
Result = CAST(newtoken as nvarchar(max))
FROM
T
JOIN #retention1 r1
ON r1.ID = T.ID
CROSS APPLY(
SELECT newstartidx = EndIdx + 1
) calc1
CROSS APPLY(
SELECT newtxt = substring(r1.txt, newstartidx, len(r1.txt))
) calc2
CROSS APPLY(
SELECT patidx = charindex(' ', newtxt)
) calc3
CROSS APPLY(
SELECT newendidx = CASE
WHEN patidx = 0 THEN len(newtxt)
ELSE patidx END
) calc4
CROSS APPLY(
SELECT newtoken = substring(r1.txt, newstartidx, newendidx)
) calc5
WHERE newendidx > 0
)
SELECT
ID,
--Result
Name = left(Result, eqIdx - 1),
Value = substring(Result, eqIdx + 1, len(Result) - eqIdx + 1)
FROM
T
OUTER APPLY (
SELECT eqIdx = charindex('=', Result)
) calc6
WHERE
Row != 0
AND eqIdx != 0
ORDER BY ID
Since there are more than one expressions to parse in the table, you would have problems referencing them without an identifier. So, i added ID to your temporary table.
The output from CTE also contains ID which you can use as a reference to #retention1.ID.

String handling galore with a little cheating: Extending #p_string with a space at the begining and the end.
DECLARE #P_string nvarchar (100), #P_variable nvarchar (100)
set #p_variable = ' Action='
set #p_string = ' hello Action=Refer non-action=non-refer '
select substring(substring(#p_string, charindex(upper(#P_variable),upper(#P_string))+1, len(#p_string)-len(#p_variable)),charindex('=',substring(#p_string, charindex(upper(#P_variable),upper(#P_string))+1, len(#p_string)-len(#p_variable)))+1,CHARINDEX(' ', substring(#p_string, charindex(upper(#P_variable),upper(#P_string))+1, len(#p_string)-len(#p_variable)))-LEN(#P_variable))
set #p_string = ' bye Action=Follow non-action=non-refer '
select substring(substring(#p_string, charindex(upper(#P_variable),upper(#P_string))+1, len(#p_string)-len(#p_variable)),charindex('=',substring(#p_string, charindex(upper(#P_variable),upper(#P_string))+1, len(#p_string)-len(#p_variable)))+1,CHARINDEX(' ', substring(#p_string, charindex(upper(#P_variable),upper(#P_string))+1, len(#p_string)-len(#p_variable)))-LEN(#P_variable))
set #p_string = ' hello non-action=non-refer Action=compare '
select substring(substring(#p_string, charindex(upper(#P_variable),upper(#P_string))+1, len(#p_string)-len(#p_variable)),charindex('=',substring(#p_string, charindex(upper(#P_variable),upper(#P_string))+1, len(#p_string)-len(#p_variable)))+1,CHARINDEX(' ', substring(#p_string, charindex(upper(#P_variable),upper(#P_string))+1, len(#p_string)-len(#p_variable)))-LEN(#P_variable))

SQL Server - find nth occurrence in a string

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?

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

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 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

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

This does not directly answer the question, but as I have found this while looking for a solution for extracting multiple values from a single string, with a specific delimiter, I post it anyway in case it could help someone.
SQL Server ships with the function PARSENAME that can extract up to 4 elements in a dot separated string, from the right :
SELECT PARSENAME('1234.5437.43278.532', 2) as third_element
--43278
You could use this function to retrieve the 2nd to the 5th element of the file name, by selecting from the second element to the end of the filename, without the extension.
Note that the code to remove the file extension (the 4th position from the right) is hardcoded here, so it's better to change it if you have some mix with .jpg and .jpeg file extensions for instance.
DECLARE #t TABLE (
c_filename VARCHAR(1000)
) INSERT #t
values
('abc_1_2_3_4.gif'),
('abcdefgh_1231_78432_398389_12144.png')
SELECT
LEFT(
c_filename,
CHARINDEX('_', c_filename) -1
) as first_element,
PARSENAME(
REPLACE(
/* PARSENAME only works with 4 elements */
/* we remove :
- the 1st element
- and the file extension */
SUBSTRING(
c_filename,
CHARINDEX('_', c_filename) + 1,
LEN(c_filename) - CHARINDEX('_', c_filename) -4
),
'_',
'.'
),
4 -- change this to get the nth element
) as second_element,
PARSENAME(
REPLACE(
SUBSTRING(
c_filename,
CHARINDEX('_', c_filename) + 1,
LEN(c_filename) - CHARINDEX('_', c_filename) -4
),
'_',
'.'
),
3
) as third_element,
PARSENAME(
REPLACE(
SUBSTRING(
c_filename,
CHARINDEX('_', c_filename) + 1,
LEN(c_filename) - CHARINDEX('_', c_filename) -4
),
'_',
'.'
),
2
) as fourth_element,
PARSENAME(
REPLACE(
SUBSTRING(
c_filename,
CHARINDEX('_', c_filename) + 1,
LEN(c_filename) - CHARINDEX('_', c_filename) -4
),
'_',
'.'
),
1
) as fifth_element
FROM
#t
+---------------+----------------+---------------+----------------+---------------+
| first_element | second_element | third_element | fourth_element | fifth_element |
+---------------+----------------+---------------+----------------+---------------+
| abc | 1 | 2 | 3 | 4 |
| abcdefghijkl | 12qwerty31 | 78891432 | 398977389 | 1212345344 |
+---------------+----------------+---------------+----------------+---------------+

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