I have a table that has 2 simple fields: RoomNumber & RoomEarned
I would like to group the rooms together that have multiple RoomEarned Values and combine their sum. Basically adding the value together inline.
basically making this table..
RoomNumber | RoomEarned
1 | 13.23
2 | 23.79
3 | 50.75
4 | 32.90
10 | 11.31
11 | 31.83
12 | 13.92
12 | 18.82
13 | 41.87
14 | 87.74
15 | 100.83
into this...
RoomNumber | RoomEarned
1 | 13.23
2 | 23.79
3 | 50.75
4 | 32.90
10 | 11.31
11 | 31.83
12 | 32.74
13 | 41.87
14 | 87.74
15 | 100.83
Obviously its a grouping function, but to my abilities.. I fall terribly short.
any ideas?
select RoomNumber, SUM(RoomEarned) from MyTable group by RoomNumber
Related
Sorry if this is a noob question!
I have two tables - a movie and a comment table.
I am trying to return output of the movie name and each comment for that movie as long as that movie has more than 1 comment associated to it.
Here are my tables
test_movies=# SELECT * FROM movie;
id | name | rating | release_date | original_copy_location
----+------------------------------------+--------+--------------+------------------------
1 | Cruella | 9 | 2021-05-28 | 4
7 | Shutter Island | 9 | 2010-02-19 | 4
9 | Grown Ups | 7 | 2010-06-25 | 4
11 | Guardians of the Galaxy: Volume 1 | 8 | 2014-09-01 | 4
14 | The RIng | 8 | 2002-10-18 | 4
17 | Digimon: The Movie | 6 | 2000-01-10 | 4
19 | Star Wars Episode 1 | 5 | 1999-06-21 | 4
20 | Ghosts Of Mars | 5 | 1998-09-15 | 4
5 | Interstellar | 8 | 2014-11-07 | 1
10 | Mean Girls | 8 | 2004-04-30 | 1
12 | Captain America: The First Avenger | 7 | 2011-07-22 | 1
15 | Get Out | 6 | 2017-02-24 | 1
6 | The Dark Knight | 10 | 2008-07-18 | 2
16 | Pokemon: The First Movie | 5 | 1998-11-10 | 2
18 | The Last Dance | 8 | 2020-05-01 | 2
8 | Just Go With It | 8 | 2011-02-11 | 3
13 | The Blair Witch Project | 8 | 1999-08-29 | 3
(17 rows)
test_movies=# SELECT * FROM comments;
c_id | c_comment | c_movie | c_user
------+--------------------------------------+---------+--------
1 | testing comment 1 | 16 | 4
2 | testing comment 1 | 1 | 1
3 | testing comment 1 | 1 | 2
4 | testing comment 1 | 8 | 5
5 | testing comment 1 | 6 | 3
6 | testing comment 1 | 12 | 2
7 | testing comment 1 | 20 | 3
8 | testing comment 1 | 16 | 5
9 | testing comment 1 | 17 | 4
10 | testing comment 1 | 12 | 2
(10 rows)
Output im trying to get is this:
name | c_comment
------------------------+-------------------------------------
Cruella | testing comment 1
Curella | testing comment 1
Pokemon:The First Movie | testing comment 1
Pokemon:The First Movie | testing comment 1
Captain America | testing comment 1
Captain America | testing comment 1
The problem with my queries is that I can't figure out how to return both the movie name and comment associated with it using aggregate functions.
If I use the count in the first select statement it returns all rows:
SELECT m.name, c.c_comment FROM movie m, comments c WHERE m.id = c.c_movie GROUP BY m.name, c.c_comment HAVING COUNT(m.name) >= 1;
If I try the below subquery I get the error - ERROR: subquery must return only one column
SELECT m.name, c.c_comment FROM movie m, comments c WHERE m.id = c.c_movie AND(SELECT m.name, COUNT(c.c_movie) FROM movie m, comments c WHERE m.id =c.c_movie GROUP BY name HAVING COUNT(c.c_movie) > 1);
Still a bit new to SQL as I'm a student and having a tough time figuring this query out lol.
Thanks in advance!
Something like this could work
select m.name, c.c_comment
from movie m
join comment c
on c.c_movie = m.id
where exists (select 1 from comments cc where cc.c_movie=m.id group by c_movie having count(*)>1)
It's standard sql, but you cannot work with mysql and postgresql at the same time... 🤔
Use window functions!
select m.name, c.c_comment
from movie m join
(select c.*, count(*) over (partition by c_movie) as cnt
from comment c
) c
on c.c_movie = m.id
where cnt > 1;
I have the following SQL Server tables (with sample data):
Questionnaire
id | coachNodeId | youngPersonNodeId | complete
1 | 12 | 678 | 1
2 | 12 | 52 | 1
3 | 30 | 99 | 1
4 | 12 | 678 | 1
5 | 12 | 678 | 1
6 | 30 | 99 | 1
7 | 12 | 52 | 1
8 | 30 | 102 | 1
Answer
id | questionnaireId | score
1 | 1 | 1
2 | 2 | 3
3 | 2 | 2
4 | 2 | 5
5 | 3 | 5
6 | 4 | 5
7 | 4 | 3
8 | 5 | 4
9 | 6 | 1
10 | 6 | 3
11 | 7 | 5
12 | 8 | 5
ContentNode
id | text
12 | Zak
30 | Phil
52 | Jane
99 | Ali
102 | Ed
678 | Chris
I have the following T-SQL query:
SELECT
Questionnaire.id AS questionnaireId,
coachNodeId AS coachNodeId,
coachNode.[text] AS coachName,
youngPersonNodeId AS youngPersonNodeId,
youngPersonNode.[text] AS youngPersonName,
ROW_NUMBER() OVER (PARTITION BY Questionnaire.coachNodeId, Questionnaire.youngPersonNodeId ORDER BY Questionnaire.id) AS questionnaireNumber,
score = (SELECT AVG(score) FROM Answer WHERE Answer.questionnaireId = Questionnaire.id)
FROM
Questionnaire
LEFT JOIN
ContentNode AS coachNode ON Questionnaire.coachNodeId = coachNode.id
LEFT JOIN
ContentNode AS youngPersonNode ON Questionnaire.youngPersonNodeId = youngPersonNode.id
WHERE
(complete = 1)
ORDER BY
coachNodeId, youngPersonNodeId
This query outputs the following example data:
questionnaireId | coachNodeId | coachName | youngPersonNodeId | youngPersonName | questionnaireNumber | score
1 | 12 | Zak | 678 | Chris | 1 | 1
2 | 12 | Zak | 52 | Jane | 1 | 3
3 | 30 | Phil | 99 | Ali | 1 | 5
4 | 12 | Zak | 678 | Chris | 2 | 4
5 | 12 | Zak | 678 | Chris | 3 | 4
6 | 30 | Phil | 99 | Ali | 2 | 2
7 | 12 | Zak | 52 | Jane | 2 | 5
8 | 30 | Phil | 102 | Ed | 1 | 5
To explain what's happening here… There are various coaches whose job is to undertake questionnaires with various young people, and log the scores. A coach might, at a later date, repeat the questionnaire with the same young person several times, hoping that they get a better score. The ultimate goal of what I'm trying to achieve is that the managers of the coaches want to see how well the coaches are performing, so they'd like to see whether the scores for the questionnaires tend to go up or not. The window function represents a way to establish how many times the questionnaire has been undertaken by the same coach/young person combo.
I need to be able to determine the average score based on the questionnaire number. So for example, the coach 'Zak' logged scores of '1' and '3' for his first questionnaires (where questionnaireNumber = 1) so the average would be 2. For his second questionnaires (where questionnaireNumber = 2) the scores were '3' and '5' so the average would be 4. So in analysing this data we know that over time Zak's questionnaire scores have improved from an average of '2' the first time to an average of '4' the second time.
I feel like the query needs to be grouped by the coachNodeId and questionnaireNumber values so it would output something like this (I've ommitted the questionnaireId, youngPersonNodeId, youngPersonName and score columns as they aren't crucial for the output — they're only used to derive the averageScore — and wouldn't be useful the way the results are grouped):
coachNodeId | coachName | questionnaireNumber | averageScore
12 | Zak | 1 | 2 (calculation: (1 + 3) / 2)
12 | Zak | 2 | 4 (calculation: (3 + 5) / 2)
12 | Zak | 3 | 4 (only one value: 4)
30 | Phil | 1 | 5 (calculation: (5 + 5) / 2)
30 | Phil | 2 | 2 (only one value: 2)
Could anyone suggest how I can modify my query to output the average scores based on the score from the sub-query and the ROW_NUMBER window function? I've hit the limits of my SQL skills!
Many thanks.
It is a bit hard to tell without sample data, but I think you are describing aggregation:
SELECT q.coachNodeId AS coachNodeId,
cn.[text] AS coachName,
q.youngPersonNodeId AS youngPersonNodeId,
ypn.[text] AS youngPersonName,
AVG(score)
FROM Questionnaire q JOIN
ContentNode cn
ON q.coachNodeId = cn.id JOIN
ContentNode ypn
ON q.youngPersonNodeId = ypn.id LEFT JOIN
Answer a
ON a.questionnaireId = q.id
WHERE complete = 1
GROUP BY q.coachNodeID, cn.[text] AS coachName,
q.youngPersonNodeId, ypn.[text]
I'm trying to solve the bus routing problem in postgresql which requires visibility of previous and next rows. Here is my solution.
Step 1) Have one edges table which represents all the edges (the source and target represent vertices (bus stops):
postgres=# select id, source, target, cost from busedges;
id | source | target | cost
----+--------+--------+------
1 | 1 | 2 | 1
2 | 2 | 3 | 1
3 | 3 | 4 | 1
4 | 4 | 5 | 1
5 | 1 | 7 | 1
6 | 7 | 8 | 1
7 | 1 | 6 | 1
8 | 6 | 8 | 1
9 | 9 | 10 | 1
10 | 10 | 11 | 1
11 | 11 | 12 | 1
12 | 12 | 13 | 1
13 | 9 | 15 | 1
14 | 15 | 16 | 1
15 | 9 | 14 | 1
16 | 14 | 16 | 1
Step 2) Have a table which represents bus details like from time, to time, edge etc.
NOTE: I have used integer format for "from" and "to" column for faster results as I can do an integer query, but I can replace it with any better format if available.
postgres=# select id, "busedgeId", "busId", "from", "to" from busedgetimes;
id | busedgeId | busId | from | to
----+-----------+-------+-------+-------
18 | 1 | 1 | 33000 | 33300
19 | 2 | 1 | 33300 | 33600
20 | 3 | 2 | 33900 | 34200
21 | 4 | 2 | 34200 | 34800
22 | 1 | 3 | 36000 | 36300
23 | 2 | 3 | 36600 | 37200
24 | 3 | 4 | 38400 | 38700
25 | 4 | 4 | 38700 | 39540
Step 3) Use dijkstra algorithm to find the nearest path.
Step 4) Get the upcoming buses from the busedgetimes table in the earliest first order for the nearest path detected by dijkstra algorithm.
Problem: I am finding it difficult to make the query for the Step 4.
For example: If I get the path as edges 2, 3, 4, to travel from source vertex 2 to target vertex 5 in the above records. To get the first bus for the first edge, it's not so hard as I can simply query with from < 'expected departure' order by from desc but for the second edge, the from condition requires to time of first result row. Also, query requires edge ids filter.
How can I achieve this in a single query?
I am not sure if I understood your problem correctly. But getting values from other rows this can be done by window functions (https://www.postgresql.org/docs/current/static/tutorial-window.html):
demo: db<>fiddle
SELECT
id,
lag("to") OVER (ORDER BY id) as prev_to,
"from",
"to",
lead("from") OVER (ORDER BY id) as next_from
FROM bustimes;
The lag function moves the value of the previous row into the current one. The lead function does the same with the next row. So you are able to calculate a difference between last arrival and current departure or something like that.
Result:
id prev_to from to next_from
18 33000 33300 33300
19 33300 33300 33600 33900
20 33600 33900 34200 34200
21 34200 34200 34800 36000
22 34800 36000 36300
Please notice that "from" and "to" are reserved words in PostgreSQL. It would be better to chose other names.
I have two SQL tables. Table 1 is as follows:
SALEREF
1 | 40303020
2 | 40303021
3 | 40303021
4 | 40303021
5 | 41210028
6 | 4120302701
7 | 41210030
8 | 4112700803
9 | 4112700803
10 | 41215030
11 | 41215026
12 | 41215026
13 | 41215026
14 | 41215026
15 | 41215026
16 | 41215026
17 | 41215026
18 | 41215027
19 | 41215027
20 | 41215027
Table 2 ("LEDGER") is as follows:
SALESREF SALEDATE
0 | 4081200201 | 20140804
1 | 40303020 | 20141015
2 | 40303021 | 20141017
3 | 40303021 | 20141017
4 | 40303021 | 20141017
5 | 41210028 | 20121214
6 | 4120302701 | 20130926
7 | 41210030 | 20130926
8 | 4112700803 | 20131107
9 | 4112700803 | 20131107
10 | 41215030 | 20120720
What I am looking for is a single line that outputs the following:
TotalDistinctSalesRefsInTable1 HighestSaleDateValueInTable2 (that has a matching value in table 1)
9 20141017
the total number of distinct SALESREF's in table 1 and the latest SALESDATE value from table 2.
I've tried selecting within a query but quickly found the limitation of my knowledge although I know I can get the latest overall sale date by doing:
SELECT MAX(LEDGER.SALEDATE) AS LAST_DATE FROM LEDGER
I just need help piecing the whole thing together.
you can use left join , count and max to get your desired result
select count(distinct t1.salesref) as TotalDistinctSalesRefsInTable1,
ifnull(max(l.saledate),0) as HighestSaleDateValueInTable
from table1 t1
left join ledger l
on t1.salesref = l.salesref
I am very new to postgresql and would like to generate some summary data from our table
We have a simple message board - table name messages which has an element ctg_uid. Each ctg_uid corresponds to a category name in the table categories.
Here are the categories select * from categories ORDER by ctg_uid ASC;
ctg_uid | ctg_category | ctg_creator_uid
---------+--------------------+-----------------
1 | general | 1
2 | faults | 1
3 | computing | 1
4 | teaching | 2
5 | QIS-FEEDBACK | 3
6 | QIS-PHYS-FEEDBACK | 3
7 | SOP-?-CHANGE | 3
8 | agenda items | 7
10 | Acq & Process | 2
12 | physics-jobs | 3
13 | Tech meeting items | 12
16 | incident-forms | 3
17 | ERRORS | 3
19 | Files | 10
21 | QIS-CAR | 3
22 | doses | 4
24 | admin | 3
25 | audit | 3
26 | For Sale | 4
31 | URGENT-REPORTS | 4
34 | dt-jobs | 3
35 | JOBS | 3
36 | IN-PATIENTS | 4
37 | Ordering | 4
38 | dep-meetings | 4
39 | reporting | 4
What I would like to do is for all messages on our messages is count the frequency of each category
I can do it on a category by category basis
SELECT count(msg_ctg_uid) FROM messages where msg_ctg_uid='13';
However is it possible to do this in a one liner?
The following gives the the category and ctg_uid for each message
SELECT ctg_category, msg_ctg_uid FROM messages INNER JOIN categories ON (ctg_uid = msg_ctg_uid);
but SELECT ctg_category, count(msg_ctg_uid) FROM messages INNER JOIN categories ON (ctg_uid = msg_ctg_uid);
gives me the error ERROR: column "categories.ctg_category" must appear in the GROUP BY clause or be used in an aggregate function
How do I aggregate the frequency of each category ?
You're missing the group by clause:
SELECT ctg_category, count(msg_ctg_uid)
FROM messages INNER JOIN categories ON (ctg_uid = msg_ctg_uid);
GROUP BY ctg_category
this means you want the count per ctg_category