MySQL NOT IN from another column in the same table

Question

I want to run a mysql query to select all rows from a table films where the value of the title column does not exist anywhere in all the values of another column (collection).

Here is a simplified version of my table with content:

mysql> select * from films;
+----+--------------+--------------+
| id | title        | collection   |
+----+--------------+--------------+
|  1 | Collection 1 | NULL         |
|  2 | Film 1       | NULL         |
|  3 | Film 2       | Collection 1 |
+----+--------------+--------------+

Here is my query:

mysql> SELECT * FROM films WHERE title NOT IN (SELECT collection FROM films);
Empty set (0.00 sec)

In this example, I would want to select the rows with titles Film 1 and Film 2, but my query is returning no rows.

Here is the table structure:

CREATE TABLE `films` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(200) NOT NULL DEFAULT '',
  `collection` varchar(200) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM;

The reason you're not retuning any rows is because NULL isn't being considered in the result set. I have a sneaking suspicion if you replace NULL with an empty string, this may fix your problem. — Joshua Burns, Jan 09 '13 at 20:19
@JoshuaBurns I tested this and it doesn't seem to be the issue. — Kermit, Jan 09 '13 at 20:20
This is a dup of http://stackoverflow.com/questions/1001144/mysql-select-x-from-a-where-not-in-select-x-from-b-unexpected-result — thang, Jan 09 '13 at 20:29

score 17 · Accepted Answer · answered Jan 09 '13 at 20:27

17

SELECT * 
FROM films 
WHERE title NOT IN (SELECT collection FROM films where collection is not null);

SQLFiddle: http://sqlfiddle.com/#!2/76278/1

answered Jan 09 '13 at 20:27

+1 I think you posted this while I was editing mine with the `IN` version as well – Taryn Jan 09 '13 at 20:29
Thanks, I'm accepting yours because it's the first correct answer (and the one I'm going to use). Could you explain why the `is not null` makes it work? – jessica Jan 09 '13 at 21:55
3

*is not null* is needed because the semantic specification of *not in* requires that the set can't contain any null element. See documentation at http://dev.mysql.com/doc/refman/5.0/en/comparison-operators.html where it says *To comply with the SQL standard, IN returns NULL not only if the expression on the left hand side is NULL, but also if no match is found in the list and one of the expressions in the list is NULL.* – thang Jan 09 '13 at 22:43

score 6 · Answer 2 · edited May 23 '17 at 11:54

Have you tried using NOT EXISTS:

SELECT * 
FROM films f1
WHERE NOT EXISTS (SELECT collection 
                  FROM films f2
                  WHERE f1.title = f2.collection);

See SQL Fiddle with Demo

If you want to use IN then you will want to look for values that are NOT NULL:

SELECT * 
FROM films 
WHERE title NOT IN (SELECT collection 
                    FROM films
                    WHERE collection is not null);

See SQL Fiddle with Demo

The result for both is:

| ID |  TITLE |   COLLECTION |
------------------------------
|  2 | Film 1 |       (null) |
|  3 | Film 2 | Collection 1 |

The problem with your current query is that -- stealing from @Quassnoi's answer here:

Both IN and NOT IN return NULL which is not an acceptable condition for WHERE clause.

Since the null value is being returned by your subquery you want to specifically exclude it.

@jessica you requested additional details on why you need to filter out `null` values from the subquery -- see [this link](http://explainextended.com/2009/09/15/not-in-vs-not-exists-vs-left-join-is-null-sql-server/) or [this one](http://stackoverflow.com/questions/2246772/whats-the-difference-between-not-exists-vs-not-in-vs-left-join-where-is-null). Or even this [question answered](http://stackoverflow.com/questions/1001144/mysql-select-x-from-a-where-not-in-select-x-from-b-unexpected-result) by the same person who wrote those articles. — Taryn, Jan 09 '13 at 22:16

bonCodigo · Answer 3 · 2013-01-09T20:58:05.867

0

Try this please:

SQLFIDDLE DEMO

Query:

select a.id, a.planid
from one a
left join one b
on a.planid <> b.iid
where not (b.iid is null)
group by b.id
;

Results: based on the sample table I used.

ID      PLANID
t15     1
j18     2

EDIT TO ADD : HERE WITH OP SCHEMA

select b.id, b.title
from opschema b
inner join opschema a
on b.title <> a.collection
or b.collection <> a.title
group by b.id 
;

OP SHCEMA SQLFIDDLE DEMO

ID  TITLE
2   Film 1
3   Film 2

edited Jan 09 '13 at 20:58

answered Jan 09 '13 at 20:25

bonCodigo

14,268
1
48
91

1

This answer doesn't follow OP's schema. – Kermit Jan 09 '13 at 20:25
@njk my logic is correct though :) I have also added OP's schema. – bonCodigo Jan 09 '13 at 20:30
@Jessica please give a try on this one as well and comment. :) – bonCodigo Jan 09 '13 at 20:31

score 0 · Answer 4 · answered Jan 09 '13 at 20:33

0

Another option using an outer join

SELECT f.* 
FROM films f LEFT OUTER JOIN films ff
ON f.title = ff.collection
WHERE ff.collection IS NULL

answered Jan 09 '13 at 20:33

EvilBob22

732
5
12

score 0 · Answer 5 · edited Aug 28 '14 at 12:59

CREATE TABLE IF NOT EXISTS `reservation_tables` (
  `res_table_id` int(10) NOT NULL AUTO_INCREMENT,
  `res_table_name` int(10) NOT NULL,
  `date_time` varchar(20) NOT NULL,
  `partyhall_id` int(10) NOT NULL,
  `flag` enum('0','1') NOT NULL DEFAULT '0',
  PRIMARY KEY (`res_table_id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=9 ;


INSERT INTO `reservation_tables` (`res_table_id`, `res_table_name`, `date_time`, `partyhall_id`, `flag`) VALUES
(1, 1, '2014-08-17 12:00 am', 7, '1'),
(2, 2, '2014-08-17 12:00 am', 7, '1'),
(3, 3, '2014-08-18 12:00 am', 8, '1'),
(4, 4, '2014-08-18 12:00 am', 8, '1'),
(5, 1, '2014-08-25 12:00 am', 12, '1'),
(6, 2, '2014-08-25 12:00 am', 12, '1'),
(7, 3, '2014-08-20 12:00 am', 23, '1'),
(8, 4, '2014-08-20 12:00 am', 23, '1');

Ι had to select available table name for matching date_time

Example select available table_name where date_time = 2014-08-18 12:00 am.

solution query is: im sure this works well

SELECT distinct res_table_name FROM reservation_tables WHERE `res_table_name` NOT IN   
(SELECT `res_table_name` FROM reservation_tables where `date_time` = '2014-08-17 12:00 am')

MySQL NOT IN from another column in the same table

5 Answers5

EDIT TO ADD : HERE WITH OP SCHEMA

Linked