Joining table to itself and selecting values that don't match - mysql

Question

I want to get all data in id's 1-3 that are NOT in id's > 6
I'm using id's for simplicity, but I'm really using timestamps.
CREATE TABLE test (
id bigint(20) NOT NULL AUTO_INCREMENT,
data varchar(3) NOT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO test (id, data) VALUES
(1, 'abc'),
(2, 'def'),
(3, 'ghi'),
(4, 'jkl'),
(5, 'mno'),
(6, 'pqr'),
(7, 'def'),
(8, 'vxw'),
(9, 'yz');
One query of the dozens that I've tried.
SELECT
t1.data t1_data,
t2.data t2_data
FROM test t1
JOIN test t2
ON t2.id BETWEEN 1 AND 3
AND t1.id > 6
AND t1.data <> t2.data
So I want to get this result:
+----------+
| data |
+----------+
| abc |
| ghi |
+----------+

Answer 1

SELECT t1.data AS t1_data
FROM test t1
WHERE t1.id BETWEEN 1 AND 3
AND NOT EXISTS(
SELECT *
FROM test t2
WHERE t2.data = t1.data
AND t2.id > 6
);

Answer 2

This is an example of a set-within-sets subquery. I like to approach these using aggregation with the having clause, because this is the most general approach. In your case:
select t1.data
from test t1
group by t.data
having sum(id between 1 and 3) > 0 and
sum(id > 6) = 0;
The conditions in the having clause count the number of rows that meet each condition. The first says that there is at least one row (for a given data) with the id between 1 and 3. The second says there are no rows where the id is greater than 6.

Answer 3

You can use a NOT EXISTS clause:
SELECT DISTINCT t1.data
FROM test t1
WHERE t1.id BETWEEN 1 AND 3
AND NOT EXISTS
(
SELECT 1
FROM test t2
WHERE t2.data = t1.data
AND t2.id > 6
);
I'm using DISTINCT here because I assume it's possible for example to have a data value with id=2 and the same data value with id=3. Remove it as necessary.

Answer 4

There are a couple ways to do it (probably performance-wise an outer join might be best) but conceptually it is this:
SELECT t1.data
FROM test t1
WHERE t1.id < 4
AND t1.data NOT IN
(SELECT t2.data
FROM test t2
WHERE t2.id > 6)
The outer join version would look like this:
SELECT t1.data
FROM test t1 LEFT OUTER JOIN test t2
ON t1.data = t2.data and t1.id < 4 and t2.id > 6
WHERE t2.id IS NULL