Finding the position of a character from a string - sql

Question

I tried finding the position of a string with charindex function but when there are two letters in the same string, I'm not able to get the code.
My question is:
Find the postion of S from 'SyedSohail'
The output should be
Position
1
5
Could you please help me with the above
I'm writing the code in Tsql

Answer 1

You can paste the following query right inside your SQL Editor:
DECLARE #test AS varchar(100);
DECLARE #ctr as int;
DECLARE #testlength as int;
DECLARE #charToTest as char(1);
DECLARE #positions as varchar(MAX);
DECLARE #findChar as char(1);
SET #test = 'Syed Summers';
SET #ctr = 1;
SET #testlength = LEN(#test) + 1;
SET #positions = '';
SET #findChar = 'S';
WHILE #ctr < (#testlength)
BEGIN
SET #charToTest = SUBSTRING(#test, #ctr, 1)
IF (UPPER(#charToTest) = #findChar)
BEGIN
SET #positions = #positions + ',' + CONVERT(VARCHAR(10), #ctr)
END
SET #ctr = #ctr + 1
END
SELECT RIGHT(#positions, (LEN(#positions) - 1));
Explanation:
#test - will contain the string which you want to search
#ctr - counter to iterate through all the characters in your string #test
#testLength - length of your #test string
#findChar - the character which you want to count the instance in the string
#charToTest - the string being tested whether it equals your #findChar value
#positions - will be an enumerated string of the position where the #findChar was found in the #test string.
Note that I provided a simplistic answer to help guide the understanding for the person who posted the question.

Answer 2

Try to create a function like below,
CREATE FUNCTION dbo.FindPatternLocation
(
#string NVARCHAR(MAX),
#term NVARCHAR(255)
)
RETURNS TABLE
AS
RETURN
(
SELECT pos = Number - LEN(#term)
FROM (SELECT Number, Item = LTRIM(RTRIM(SUBSTRING(#string, Number,
CHARINDEX(#term, #string + #term, Number) - Number)))
FROM (SELECT ROW_NUMBER() OVER (ORDER BY [object_id])
FROM sys.all_objects) AS n(Number)
WHERE Number > 1 AND Number <= CONVERT(INT, LEN(#string)+1)
AND SUBSTRING(#term + #string, Number, LEN(#term)) = #term
) AS y);
Usage:
DECLARE #str VARCHAR(MAX) = 'SyedSohail'
SELECT pos FROM dbo.FindPatternLocation(#str, 's');
Source

Answer 3

If I understand correctly, you could use an rCTE to iterate through the string:
DECLARE #YourString varchar(12) = 'SyedSohail';
DECLARE #Char char(1) = 'S';
WITH rCTE AS(
SELECT V.YourString,
CI.I
FROM (VALUES(#YourString))V(YourString)
CROSS APPLY (VALUES(CHARINDEX(#Char,V.YourString))) CI(I)
WHERE CI.I > 0
UNION ALL
SELECT r.YourString,
CI.I
FROM rCTe r
CROSS APPLY (VALUES(CHARINDEX(#Char,r.YourString,r.I+1))) CI(I)
WHERE CI.I > 0)
SELECT R.I
FROM rCTE r;
However, I suspect (know for a fact), a Tally would be quicker with a dataset and/or longer values:
WITH N AS(
SELECT N
FROM (VALUES(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL))N(N)),
Tally AS(
SELECT TOP(SELECT MAX(LEN(V.YourString)) FROM (VALUES(#YourString))V(YourString)) --Should be from your tablt
ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS I
FROM N N1, N N2, N N3, N N4) --10,000 rows
SELECT T.I
FROM Tally T
CROSS JOIN (VALUES(#YourString))V(YourString)
WHERE SUBSTRING(V.YourString,T.I,1) = #Char;