splitting input string in sql and getting its value from another table - sql

Question

I have a table hobby and another table hobbyValue.
Hobby Table
===========
hobbies (It is a list of hobbies which user has inserted using checkbox. It gets stores hobby as Ids with a delimiter ^ for e.g hobbyId1^hobbyId2^hobbyId3^)
Hobby Value Table (it has two columns id, Value)
============
hobbyId1 | Football
hobbyId2 | baseball
hobbyId3 | chess
I am restricted to use this kind of table format because it is part of a big application. I am not sure how can I write a sql function where input string is hobbies from Hobby table and out put will be its values.
for e.g.
============================
string inputHobbies = hobbies from Hobby table , hobbyId1^hobbyId2^hobbyId3^
outputValues = input my_sql_function(inputHobbies)
outputValues should be football,baseball,chess
I dont even know how should I start for to get this.

Answer 1

Firstly, you will need some string split capability. If you are on Sql Server 2016+, there should be built in STRING_SPLIT function (https://learn.microsoft.com/en-us/sql/t-sql/functions/string-split-transact-sql).
If not, you can use one below, which I've got some time ago from another SO question.
CREATE FUNCTION fnc_splitstring ( #stringToSplit VARCHAR(MAX) )
RETURNS
#returnList TABLE ([Name] [nvarchar] (500))
AS
BEGIN
DECLARE #name NVARCHAR(255)
DECLARE #pos INT
WHILE CHARINDEX('^', #stringToSplit) > 0
BEGIN
SELECT #pos = CHARINDEX('^', #stringToSplit)
SELECT #name = SUBSTRING(#stringToSplit, 1, #pos-1)
INSERT INTO #returnList
SELECT #name
SELECT #stringToSplit = SUBSTRING(#stringToSplit, #pos+1, LEN(#stringToSplit)-#pos)
END
INSERT INTO #returnList
SELECT #stringToSplit
RETURN
END
Then you can split your hobby ids and join them onto the Hobby table, get the actual name and STUFF the results into a single result row again:
CREATE FUNCTION fnc_getHobbies (#listOfHobbyIds NVARCHAR(MAX))
RETURNS NVARCHAR(MAX)
AS
BEGIN
DECLARE #hobbies NVARCHAR(MAX)
SELECT #hobbies = STUFF(( SELECT ',' + hobby
FROM dbo.fnc_splitstring(#listOfHobbyIds) hb
INNER JOIN hobby h on h.id = hb.name
FOR XML PATH('')
), 1, 1, '')
RETURN #hobbies
END
End usage like below:
SELECT dbo.fnc_getHobbies(hobbyids)
FROM hobbies
Lastly, here is the SQL Fiddle for this: http://sqlfiddle.com/#!18/44cd9

Answer 2

CREATE FUNCTION [dbo].[SplitForDelimiter] -- a table-valued function
(
#delimiter VARCHAR(10),
#input VARCHAR(1000)
)
RETURNS #tempTable TABLE(
data VARCHAR(100)
)
BEGIN
DECLARE #tempstr VARCHAR(1000)
SET #tempstr = #input
WHILE(charindex(#delimiter,#tempstr,0) > 0)
BEGIN
DECLARE #t VARCHAR(100)
SET #t = Substring(#tempstr,0,(charindex(#delimiter,#tempstr,0)))
INSERT into #tempTable (data) VALUES (#t)
SET #tempstr = Substring(#tempstr,charindex(#delimiter,#tempstr,0)+1,Len(#tempstr))
if(charindex(#delimiter,#tempstr,0) <=0)
BEGIN
INSERT into #tempTable (data) VALUES (#tempstr)
END
END
Then
SELECT Value from HobbyValue HV
WHERE ID IN (select * from SplitForDelimiter('^','hobbyId1^hobbyId2^hobbyId3^'))