subquery in IN clause? - mysql

Question

I have two tables named as
product_Category
CREATE TABLE `product_category` (
`pid` int(11) NOT NULL,
`cid` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
--
-- Dumping data for table `product_category`
--
/*!40000 ALTER TABLE `product_category` DISABLE KEYS */;
INSERT INTO `product_category` (`pid`,`cid`) VALUES
(1,1),
(2,3),
(3,2),
(4,2),
(5,3),
(1,2),
(2,4),
(3,1);
and category table
CREATE TABLE `category` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`cat_name` varchar(50) NOT NULL,
`mapped_cat_id` varchar(250) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1;
--
-- Dumping data for table `category`
--
/*!40000 ALTER TABLE `category` DISABLE KEYS */;
INSERT INTO `category` (`id`,`cat_name`,`mapped_cat_id`) VALUES
(1,'c1','1,2,4'),
(2,'c2','2,3'),
(3,'c3','3,4'),
(4,'c4','4,1,3');
/*!40000 ALTER TABLE `category` ENABLE KEYS */;
When I run this query
select distinct pid from
product_category where cid in (1,2,4)
I got result of pid (1,3,4,2)
but when I run query
select distinct pid from
product_category where cid in (select mapped_cat_id from category where id=1)
I got result of pid (1,3)
How to use subquery with 'IN' clause ?
I know my way of asking question is wrong because I dont know how to create table here thats why I wrote query instead of table.

Answer 1

i think coma separated values are not good.
Delete contents of your category table and use following query to insert
INSERT INTO `category` (`id`, `cat_name`, `mapped_cat_id`) VALUES
(1, 'c1', '1'),
(2, 'c2', '2'),
(3, 'c3', '3'),
(4, 'c4', '4'),
(5, 'c1', '2'),
(6, 'c1', '4'),
(7, 'c2', '3'),
(8, 'c3', '4'),
(9, 'c4', '1'),
(10, 'c4', '3');
Then use following query to get your result
select distinct pid from
product_category where cid in
(select mapped_cat_id from category where cat_name='c1')

Answer 2

You might be looking for FIND_IN_SET() function
select distinct pid from
product_category where FIND_IN_SET(cid,
(select mapped_cat_id from category where id=1));
SAMPLE FIDDLE
Since mapped_cat_id is saved as comma - seperated values(varchar), it is taking only first integer for the condition checking. Here it is 1