Assessments table:
+---------------+-----------+---------------------+
| assessment_id | device_id | created_at |
+---------------+-----------+---------------------+
| 1 | 1 | 2022-07-15 20:03:03 |
| 2 | 2 | 2022-07-15 21:03:03 |
| 3 | 1 | 2022-07-15 22:03:03 |
| 4 | 2 | 2022-07-15 23:03:03 |
| 5 | 2 | 2022-07-15 23:03:03 |
+---------------+-----------+---------------------+
Results table:
+---------------+---------+--------+
| assessment_id | test | result |
+---------------+---------+--------+
| 1 | A | PASS |
| 2 | B | FAIL |
| 3 | A | FAIL |
| 4 | B | PASS |
| 5 | B | PASS |
+---------------+---------+--------+
Objective
I would like to return a row for each time the result of a test_id changes.
For example, Device 1 has Assessments 1 and 3. Test A in Assessment 1 was PASS, and Test A in Assessment 3 was FAIL, so we want to return this change as a row.
Device 2 has Assessments 2, 4, and 5. There was a test result change in Assessments 2 and 4 (Test B changed from FAIL to PASS), we want to return a row for this.
We do not want to return a row for Assessment 5 because Test B was PASS, and it was also PASS in Assessment 4. No change.
The resulting table would look like this:
+-----------+---------+------------------------+----------------+----------------------+--------------------+------------+----------------------+
| device_id | test_id | previous_assessment_id | previous_value | previous_value_date | next_assessment_id | next_value | next_value_date |
+-----------+---------+------------------------+----------------+----------------------+--------------------+------------+----------------------+
| 1 | A | 1 | PASS | 15/07/2022 20:03:03 | 3 | FAIL | 15/07/2022 22:03:03 |
| 2 | B | 2 | FAIL | 15/07/2022 21:03:03 | 4 | PASS | 15/07/2022 23:03:03 |
+-----------+---------+------------------------+----------------+----------------------+--------------------+------------+----------------------+
I've tried playing around with a couple of queries found here on SO, but they either took a long time and returned the wrong data, or didn't work at all. I don't think this is a duplicate because I'm using multiple tables, and every other question I've seen refers to a single table.
I've also looked at this SO question but could not get the helpful answer to apply to my situation.
I'm having some weird issue getting SQL Fiddle to work, but here is the test schema I've been tinkering with:
CREATE TABLE `assessments` (
`id` int,
`device_id` int,
`created_at` datetime
);
INSERT INTO `so_assessments` (`id`, `device_id`, `created_at`) VALUES (1, 1, '2022-07-09 22:56:00');
INSERT INTO `so_assessments` (`id`, `device_id`, `created_at`) VALUES (2, 2, '2022-07-10 22:56:06');
INSERT INTO `so_assessments` (`id`, `device_id`, `created_at`) VALUES (3, 1, '2022-07-11 22:56:11');
INSERT INTO `so_assessments` (`id`, `device_id`, `created_at`) VALUES (4, 2, '2022-07-12 22:56:17');
INSERT INTO `so_assessments` (`id`, `device_id`, `created_at`) VALUES (5, 2, '2022-07-13 22:56:24');
CREATE TABLE `results` (
`assessment_id` int,
`test` enum('A','B'),
`result` enum('PASS','FAIL')
);
INSERT INTO `results` (`assessment_id`, `test`, `result`) VALUES (1, 'A', 'PASS');
INSERT INTO `results` (`assessment_id`, `test`, `result`) VALUES (2, 'B', 'FAIL');
INSERT INTO `results` (`assessment_id`, `test`, `result`) VALUES (3, 'A', 'FAIL');
INSERT INTO `results` (`assessment_id`, `test`, `result`) VALUES (4, 'B', 'PASS');
INSERT INTO `results` (`assessment_id`, `test`, `result`) VALUES (5, 'B', 'PASS');
If you are using MySQL 8, Window functions can help. https://dev.mysql.com/doc/refman/8.0/en/window-function-descriptions.html
You can partition your results by device and test, and add a column that is the previous value of the result, then use the last row where the result differs from the previous value.
The following query creates a new column in your results with previous_value
SELECT
assessment_id,
device_id,
test,
result,
LAG (result) over w as `previous_value`,
LAG (assessment_id) over w as `previous_assessment_id`
FROM assessments join results using(assessment_id)
WINDOW w AS (PARTITION BY device_id, test ORDER BY assessment_id)
Yields the result:
+---------------+-----------+------+--------+----------------+------------------------+
| assessment_id | device_id | test | result | previous_value | previous_assessment_id |
+---------------+-----------+------+--------+----------------+------------------------+
| 1 | 1 | A | PASS | NULL | NULL |
| 3 | 1 | A | FAIL | PASS | 1 |
| 2 | 2 | B | FAIL | NULL | NULL |
| 4 | 2 | B | PASS | FAIL | 2 |
| 5 | 2 | B | PASS | PASS | 4 |
+---------------+-----------+------+--------+----------------+------------------------+
Which is a big part of the battle. Now we need to take that result and find the row for each device/test pair with the highest assessment_id, where result != previous_value.
The window is calculated after GROUP BY, ORDER BY, and even HAVING, so there's not much more that can be done in that query (that I have thought of) to narrow it down to the only the most recent entries for each device/test pair. So the above will have to be a subquery to get the final result.
Note: I am going to assume that if the result never changes, you want to show the first time that result was recorded. In other words, you want to count results with previous_value = NULL as a transition.
Here's a query that lists all the times the test result from a device/test pair changes:
SELECT * FROM
(SELECT
assessment_id,
device_id,
test,
result,
LAG (result) over w as `previous_value`
FROM assessments join results using(assessment_id)
WINDOW w AS (PARTITION BY `device_id`, `test` ORDER BY `assessment_id`)
) AS t
WHERE result != `previous_value` OR `previous_value` IS NULL
gets the result (I left out previous_assesssment_id and the others for space):
+---------------+-----------+------+--------+----------------+
| assessment_id | device_id | test | result | previous_value |
+---------------+-----------+------+--------+----------------+
| 1 | 1 | A | PASS | NULL |
| 3 | 1 | A | FAIL | PASS |
| 2 | 2 | B | FAIL | NULL |
| 4 | 2 | B | PASS | FAIL |
+---------------+-----------+------+--------+----------------+
EDIT
That's the answer to the question. If the first time the value is set is not of interest, just delete the OR part of the WHERE clause. There rest of this answer is because I convinced myself the problem was to get the MOST RECENT time the value flipped. I'm leaving it here, but only for interest.
Carrying On
This is all the times the outcome was different than previous, plus the first time a result was recorded. Almost there.
It would be tempting at this point to add another window in the outer query to aggregate the rows from above and identify the correct rows. But at least in MySQL 8, nested windows are not supported.
But given that result, we can create a query using MAX() and GROUP BY that gives the assessment_ids of all the rows we ultimately want:
SELECT MAX(assessment_id)
FROM (
SELECT
assessment_id,
device_id,
test,
result,
LAG (result) over w as `previous_value`,
LAG (assessment_id) over w as `previous_assessment_id`
FROM assessments join results using(assessment_id)
WINDOW w AS (PARTITION BY device_id, test ORDER BY assessment_id)
) AS t
where result != previous_value OR previous_value IS NULL
GROUP BY device_id, test
Which yields:
+--------------------+
| MAX(assessment_id) |
+--------------------+
| 3 |
| 4 |
+--------------------+
Now we know exactly which rows we need; but we built all that data about the previous values, and now we need a way to join the result of that query with the result of the subquery.
Happily, MySQL 8 has a way to stash a query and use it multiple times, called Common Table Expressions, that use the WITH clause docs here. So we can create the table with all the fun data, then use it as a subquery to get the id's we ultimately want, and then join that right back with the results we just created:
WITH
transitions AS (SELECT
assessment_id,
device_id,
test,
result,
LAG (result) over w as `previous_value`,
LAG (assessment_id) over w as `previous_assessment_id`
FROM assessments join results using(assessment_id)
WINDOW w AS (PARTITION BY device_id, test ORDER BY assessment_id)
)
SELECT transitions.*
FROM transitions
JOIN (
SELECT MAX(assessment_id) as assessment_id
FROM transitions
WHERE result != previous_value OR previous_value IS NULL
GROUP BY device_id, test
) AS t2 using (assessment_id)
Giving us the final answer (with the other columns you can fill in):
+---------------+-----------+------+--------+----------------+------------------------+
| assessment_id | device_id | test | result | previous_value | previous_assessment_id |
+---------------+-----------+------+--------+----------------+------------------------+
| 3 | 1 | A | FAIL | PASS | 1 |
| 4 | 2 | B | PASS | FAIL | 2 |
+---------------+-----------+------+--------+----------------+------------------------+
The first part creates a data set that includes all the information about what came before each test. Then we write a query that gets the id's of the interesting rows in that query, then we join back to the original data set to fill in all the columns.
You can use windows functions to peek at values of previous or successive rows according to an ordering and grouping.
For example:
select *
from (
select
a.device_id,
r.test,
a.id as prev_assessment_id,
r.result as prev_result,
a.created_at as prev_value_date,
lead(a.id) over(partition by a.device_id
order by a.created_at) as next_assessment_id,
lead(r.result) over(partition by a.device_id
order by a.created_at) as next_result,
lead(a.created_at) over(partition by a.device_id
order by a.created_at) as next_value_date
from assessments a
join results r on r.assessment_id = a.id
) x
where prev_result <> next_result
Result:
device_id test prev_assessment_id prev_result prev_value_date next_assessment_id next_result next_value_date
---------- ----- ------------------- ------------ -------------------- ------------------- ------------ -------------------
1 A 1 PASS 2022-07-09 22:56:00 3 FAIL 2022-07-11 22:56:11
2 B 2 FAIL 2022-07-10 22:56:06 4 PASS 2022-07-12 22:56:17
See running example at db<>fiddle.
Note: Your setup queries (that I used) include different data, compared to your expected result.
I want to match id's of column 1 from column 2.
_________________________________
| uid | profile_id | status |
|------|-------------|-----------
| 1 | 2 | checked |
| 2 | 1 | checked |
| 3 | 4 | unchecked|
| 4 | 1 | unchecked|
| 4 | 3 | checked |
| 1 | 4 | checked |
...
This is my table. I want to show the result of same values that match from id1 to id2 and status is checked. Following is the output:
__________________________
| uid | profile_id | status |
|------|-------------|-----------
| 1 | 2 | checked |
| 2 | 1 | checked |
...
Because id1 1 check the id2 2 and vice versa.
I done the following code.
SELECT
`aa`.`uid` AS `uid`,
`aa`.`profile_id` AS `profile_id`,
`aa`.`match_type` AS `match_type`
FROM
(
`matched_profiles` `aa`
left join `matched_profiles` `ab` on(
(`aa`.`uid` = `ab`.`profile_id`)
)
)
where
(
(`aa`.`uid` = `ab`.`profile_id`)
and (`ab`.`uid` = `aa`.`profile_id`)
);
but above code also show me the unchecked result.
Great question. Because of the structure of the data int this table, you can do this by joining the table to itself. You will have two sets of data, replicas of one another.
You want to make sure there is a two-way match between uid and profile_id.
You also want the status for both directions to be checked
SELECT
a.*
FROM matched_profiles a
inner join matched_profiles a2 on
a.uid = a2.profile_id
and a.profile_id = a2.uid
and a.status = 'checked'
and a2.status = 'checked';
You have a kind of explicit/inexplicit join going on. I reformatted to be completely explicit for clarity. You just need to add a filter to make sure all status values are checked.
Below is the SQL to build your test schema, which is nice to provide when asking these questions for SO users.
create table matched_profiles (
uid int,
profile_id int,
status varchar(18)
);
insert into matched_profiles
values
(1, 2, 'checked'),
(2, 1, 'checked'),
(3, 4, 'unchecked'),
(4, 1, 'unchecked'),
(4, 3, 'checked'),
(1, 4, 'checked');
Basically, I am fairly new to SQL and I am playing around with it. It is fun and interesting and basically I am trying to select the userId and average gametime for each user who has more than one game session. This is my table below:
id | userId |gameTime |
________________________
1 | 1 | 10 |
2 | 2 | 10 |
3 | 3 | 15 |
4 | 1 | 10 |
5 | 2 | 25 |
_________________________
CREATE TABLE game_session(
id INTEGER PRIMARY KEY,
userId INTEGER NOT NULL,
gameTime DECIMAL NOT NULL);
INSERT INTO game_session VALUES
(1, 1, 10),
(2, 2, 10),
(3, 3, 15),
(4, 1, 10),
(5, 2, 25);
So I just want to display all instances of userID more than once and its total average time. I don't want to display the count row in the end.
I wrote my script but it isn't displaying the table WITHOUT THE COUNT(userID) AND it is showing the userID even for once instance, not more than 1!
This is my script:
SELECT userID, AVG(gameTime)
FROM game_session
WHERE ((SELECT COUNT(userID) FROM game_session) > 1)
GROUP BY userID
Where am I going wrong?
I believe you're looking for a having clause.
Try this out:
select userID, avg(gameTime)
from game_session
group by userID
having count(userID) > 1;
I have mysql table with hospitals and treatments(associated with sub treatments) that they provide. I need to make mysql query on the table which returns hospitals providing all treatment/sub_treatment given in a list. For example:
From table below I need hospitals providing all treatments in list: (tretament_id, sub_treatment_id) = (1-1, 1-2). So result must be hospitals with id 1 and 8.
hospital_id | treatment_id | sub_treatment_id
-------------------------------------------------
1 | 1 | 1
1 | 1 | 2
1 | 1 | 3
_________________________________________________
4 | 1 | 1
4 | 2 | 1
_________________________________________________
8 | 1 | 1
8 | 1 | 2
_________________________________________________
7 | 2 | 1
I tried WHERE IN but it works like OR so returns hospital 4 which satisfies only (1,1). How can I write an sql query like WHERE IN but which works like AND?
Try this:
SELECT hospital_id
FROM mytable
WHERE (treatment_id, sub_treatment_id) IN ((1, 1), (1, 2))
GROUP BY hospital_id
HAVING COUNT(CASE
WHEN (treatment_id, sub_treatment_id) IN ((1, 1), (1, 2))
THEN 1
END) = 2
Demo here
You can do this using group by and having:
select hospital_id
from t
where treatment_id = 1 and sub_treatment_id in (1, 2)
group by hospital_id
having count(*) = 2;
Note: This assumes that there are no duplicates in the table. That is easy enough to fix using count(distinct), but probably not necessary.
Here is a solution using GROUP_CONCAT and JOIN:
select distinct t.hospital_id
from hospitals h and treatments t ON h.id = t.hospital_id
having GROUP_CONCAT(CONCAT(t.treatment_id, '-', t.sub_treatment_id)
ORDER BY t.treatment_id, t.sub_treatment_id)
= '1-1,1-2';
For example, I have table:
id | number
-----------
1 | 1
2 | 1
3 | 1
4 | 2
5 | 2
6 | 3
i need to count unique numbers (1, 2 and 3), that is 3
i have working SQL code:
SELECT COUNT(DISTINCT `number`) AS `total` FROM `some_table`
but i don't know how better to do this with PHPActiveRecord
There is a count() function in phpAR, but you can't make it work with DISTINCT. So, I think the easiest is:
$total = SomeModel::first(['select' => 'COUNT(DISTINCT `number`) AS `total`'])->total;