sql query with join and FIND IN SET - mysql

Question

I want to get count of post subscribed by user below is my table schema , please help me with query for the same, i trie many option but could not do it
I tried and was able to get post count of user below is my query , but here i have used static user id , i want single query to list count for all users
SELECT COUNT(*)
FROM CATMAPPING INNER JOIN
POST ON CATMAPPING.pid = POST.id
where FIND_IN_SET(CATMAPPING.cid,(select selectedcatid from subscribers where id='1'));
Desire OP
Desired Output
uemail Postcount
-----------------------------
a#s.com 4
b#s.com 8
c#s.com 10
d#s.com 4
SQL fiddel link : http://sqlfiddle.com/#!9/4fff8f/2
CREATE TABLE subscribers (
`id` int(10),
`uemail` varchar(255) DEFAULT NULL,
`selectedcatid` varchar(255) DEFAULT NULL
) ;
ALTER TABLE subscribers ADD PRIMARY KEY (`id`);
ALTER TABLE subscribers MODIFY `id` int(10) unsigned NOT NULL AUTO_INCREMENT;
INSERT INTO subscribers (`uemail`, `selectedcatid`) VALUES ('a#s.com', '1'),
('b#s.com', '1,3'),
('c#s.com', '1,2,3'),
('d#s.com', '3');
CREATE TABLE POST (
`id` int(10),
`title` varchar(255) DEFAULT NULL
) ;
INSERT INTO POST (`id`, `title`) VALUES ('1', 'ABC'),
('2', 'DEF'),
('3', 'GHI'),
('4', 'JKL'),
('5', 'MNO'),
('6', 'PQR'),
('7', 'STU'),
('8', 'VXZ'),
('9', 'ASO'),
('10', 'LMO');
CREATE TABLE CATMAPPING (
`cid` int(10),
`pid` int(10) DEFAULT NULL
) ;
INSERT INTO CATMAPPING (`pid`, `cid`) VALUES ('1', '1'),
('2', '2'),
('3', '3'),
('4', '1'),
('5', '2'),
('6', '3'),
('7', '3'),
('8', '3'),
('9', '1'),
('10', '1');

Answer 1

Here is the correct query I wrote in sql server may be some syntax is diffrent but it gives me correct result I creates a table valued function and then used it for the query .
declare #tempsub as table (subid int,selectcatId int )
insert into #tempsub
select id ,string
from subscribers
CROSS APPLY [dbo].[ufn_CSVToTable] (selectedcatid)
--select * from #tempsub
-- subid is the id of the subscribes table
SELECT subid , count(*) from post p inner join CATMAPPING c on c.pid = p.id
left join #tempsub t on t.selectcatId= c.cid
group by t.subid
-- below is the code for tabled valued function it return a table for comma seprated string
create FUNCTION dbo.[ufn_CSVToTable] ( #StringInput VARCHAR(8000) )
RETURNS #OutputTable TABLE ( [String] nVARCHAR(1000) )
AS
BEGIN
DECLARE #String nVARCHAR(1000)
WHILE LEN(#StringInput) > 0
BEGIN
SET #String = LEFT(#StringInput,
ISNULL(NULLIF(CHARINDEX(',', #StringInput) - 1, -1),
LEN(#StringInput)))
SET #StringInput = SUBSTRING(#StringInput,
ISNULL(NULLIF(CHARINDEX(',', #StringInput), 0),
LEN(#StringInput)) + 1, LEN(#StringInput))
INSERT INTO #OutputTable ( [String] )
VALUES ( #String )
END
RETURN
END