I've tried this query:
SELECT X,Y,Z,COUNT(*)
FROM TABLE1
GROUP BY X,Y,Z
and my result is:
but I need the following result:
This should do the trick:
SELECT X,Y,Z,ROW_NUMBER() OVER (PARTITION BY X,Y,Z ORDER BY X,Y,Z)
FROM TABLE1
The ROW_NUMBER() will tick up for every value in the group X,Y,Z, and reset at a next group. The ORDER BY clause is used to define in what order it should tick up, and can be changed to however you wish. This is one of the analytical functions Oracle provides, and can be very useful.
Related
I have data with two rows as follows:
group_id item_no
weoifne 1
weoifne 2
I want to retrieve the max item_no for each group_id. I'm using this query:
SELECT MAX(item_no)
OVER (PARTITION BY group_id)
FROM my_table;
I need only one record because I'm embedding this query in a CASE WHEN statement to apply logic based on whether or not item_no is the highest value per group.
Desired Output:
2
Actual Output:
2
2
How do I modify my query to only output one record with the maximum item_no per group_id?
Use an aggregate function along with GROUP BY instead of an window function.
A window function, also known as an analytic function, computes values over a group of rows and returns a single result for each row. This is different from an aggregate function, which returns a single result for a group of rows.
https://cloud.google.com/bigquery/docs/reference/standard-sql/window-function-calls
SELECT group_id, MAX(item_no)
FROM my_table
GROUP BY group_id;
If you still want to use the window function, you can use DISTINCT in your script to get rid of the duplicates as shown below. DISTINCT works across all the columns
SELECT DISTINCT group_id
, MAX(item_no) OVER (PARTITION BY group_id)
FROM my_table
There is a table with the following column headers: indi_cod, ries_cod, date, time and level. Each ries_cod contains more than one indi_cod, and these indi_cod are random consecutive numbers.
Which SQL query would be appropriate to build if the aim is to find the smallest ID of each ries_cod, and at the same time bring its related information corresponding to date, time and level?
I tried the following query:
SELECT MIN (indi_cod) AS min_indi_cod
FROM my-project-01-354113.indi_cod.second_step
GROUP BY ries_cod
ORDER BY ries_cod
And, indeed, it presented me with the minimum value of indi_cod for each group of ries_cod, but I couldn't write the appropriate query to bring me the information from the date, time and level columns corresponding to each indi_cod.
I usually use some kind of ranking for this type of thing. you can use row_number, rank, or dense_rank depending on your rdbms. here is an example.
with t as(select a.*,
row_number() over (partition by ries_cod, order by indi_cod) as rn
from mytable)
select * from t where rn = 1
in addition if you are using oracle you can do this without two queries by using keep.
https://renenyffenegger.ch/notes/development/databases/SQL/select/group-by/keep-dense_rank/index
I think you just need to group by with the other columns
SELECT MIN (indi_cod), ries_cod, date, time, level AS min_indi_cod
FROM mytavke p
GROUP BY ries_cod, date, time, level
ORDER BY ries_cod
I am trying to perform ranking based on some calculation of already existing columns. I tried using the SQL RANK() function however it is showing the result as 1 for all entries even if the value of the order by (score column) is different. Please see the details below:
qu_point and ti_points are calculated columns
score column is again a derived column, however, simply sum of two columns mentioned in point 1.
I have used the SQL query as follow:
use EFR_DB
GO
select d.serial, d.question_set_id, d.correct_answers, d.total_questions, d.time_taken_seconds, q.total_time_in_secs,
(cast(d.correct_answers as float)/d.total_questions) as qu_point, ((q.total_time_in_secs-d.time_taken_seconds)/q.total_time_in_secs) as ti_point,
(((cast(d.correct_answers as float)/d.total_questions)*2) + ((q.total_time_in_secs-d.time_taken_seconds)/q.total_time_in_secs)) as score,
rank() over (partition by d.question_set_id order by score)
from daily_quiz_record d join Question_set q
on q.question_set_id=d.question_set_id
Please help me how can I do the raking which is partitioned by question_set_id and ranked on the basis of the score.
Screenshot attached for your reference.
enter image description here
You can’t use an alias defined in the select clause in the same clause. I suppose that one of your table has a column called score, otherwise your query would error - so this existing column is being used for ordering instead of the computed value.
Since your expression is lengthy, it is simpler to turn the query to a subquery, and rank in the outer query:
select
t.*,
rank() over(partition by question_set_id order by score) rn
from (
-- your existing query (without rank)
) t
i want to select first and last outcome from a subquery in oracle.
i cant use "rownum" since i am using "order by" which completely changes the sequence of "rownum".
pls suggest some solutions.
thanx fr help.
Use keep if you have an aggregation query. That is what it is designed for. It looks something like this:
select x,
max(outcome) keep (dense_rank first order by datetime asc) as first_outcome,
max(outcome) keep (dense_rank first order by datetime desc) as last_outcome,
from t
group by x;
Use first_value() and last_value() if there is no aggregation:
select t.*,
first_value(outcome) over (partition by x order by datetime) as first_outcome,
last_value(outcome) over (partition by x order by datetime) as last_outcome
from t;
You can't use "rownum" because you want both the first and the last values - otherwise you could use rownum by putting your code in a subquery and selecting from it and filtering by rownum in the outer query. As it is, you need to use ROW_NUMBER() analytic function and such (both with order by ... and with order by ... desc, so you can get both the first and the last outcome in one single outer query.
If ties are possible you may prefer DENSE_RANK to get all rows tied for first (or for last); instead, ROW_NUMBER() will return "one of" the rows tied for first (or for last); which one, specifically, is random.
If you want to see an example, provide sample data for your problem.
I solved this by using ROW_NUMBER() function with OVER(order by..).
How can I use a Distinct or Group by statement on 1 field with a SELECT of All or at least several ones?
Example: Using SQL SERVER!
SELECT id_product,
description_fr,
DiffMAtrice,
id_mark,
id_type,
NbDiffMatrice,
nom_fr,
nouveaute
From C_Product_Tempo
And I want Distinct or Group By nom_fr
JUST GOT THE ANSWER:
select id_product, description_fr, DiffMAtrice, id_mark, id_type, NbDiffMatrice, nom_fr, nouveaute
from (
SELECT rn = row_number() over (partition by [nom_fr] order by id_mark)
, id_product, description_fr, DiffMAtrice, id_mark, id_type, NbDiffMatrice, nom_fr, nouveaute
From C_Product_Tempo
) d
where rn = 1
And this works prfectly!
If I'm understanding you correctly, you just want the first row per nom_fr. If so, you can simply use a subquery to get the lowest id_product per nom_fr, and just get the corresponding rows;
SELECT * FROM C_Product_Tempo WHERE id_product IN (
SELECT MIN(id_product) FROM C_Product_Tempo GROUP BY nom_fr
);
An SQLfiddle to test with.
You need to decide what to do with the other fields. For example, for numeric fields, do you want a sum? Average? Max? Min? For non-numeric fields to you want the values from a particular record if there are more than one with the same nom_fr?
Some SQL Systems allow you to get a "random" record when you do a GROUP BY, but SQL Server will not - you must define the proper aggregation for columns that are not in the GROUP BY.
GROUP BY is used to group in conjunction with an aggregate function (see http://www.w3schools.com/sql/sql_groupby.asp), so it's no use grouping without counting, summing up etc. DISTINCT eleminates duplicates but how that matches with the other columns you want to extract, I can't imagine, because some rows will be removed from the result.