I have query to get firms by theirs sales last year.
select
Name,
Sale
from Sales
order by
Sale DESC
and I get
Firm 2 | 200 000
Firm 1 | 190 000
Firm 3 | 100 000
And I would like to get index of row in result. For Firm 2 I would like to get 0 (or 1), for Firm 3 1 (or 2) and etc. Is this possible? Or at least create some sort of autoincrement column. I can use even stored procedure if it is needed.
Firebird 3.0 supports row_number() which is the better way to do this.
However for Firebird 2.5, you can get what you want with a correlated subquery:
select s.Name, s.Sale,
(select count(*) from Sales s2 where s2.sale >= s.sale) as seqnum
from Sales s
order by s.Sale DESC;
Related
Consider the following data set that records the product sold, year, and revenue from that particular product in thousands of dollars. This data table (YEARLY_PRODUCT_REVENUE) is stored in SQL and has many more rows.
Year | Product | Revenue
2000 Table 100
2000 Chair 200
2000 Bed 150
2010 Table 120
2010 Chair 190
2010 Bed 390
Using SQL, for every year I would like to find the product that has the maximum revenue.
That is, I would like my output to be the following:
Year | Product | Revenue
2000 Chair 200
2010 Bed 390
My attempt so far has been this:
SELECT year, product, MIN(revenue)
FROM YEARLY_PRODUCT_REVENUE
GROUP BY article, month;
But when I do this, I get multiple-year values for distinct products. For instance, I'm getting the output below which is an error. I'm not entirely sure what the error here is. Any help would be much appreciated!
Year | Product | Revenue
2000 Table 100
2000 Bed 150
2010 Table 120
2010 Chair 190
You don't mention the database so I'll assume it's PostgreSQL. You can do:
select distinct on (year) * from t order by year, revenue desc
You want filtering rather than aggregation. We can use window functions (which most databases support) to rank yearly product sales, and then retain only the top selling product per year.
select *
from (
select r.*, rank() over(partition by year order by revenue desc) rn
from yearly_product_revenue r
) r
where rn = 1;
Here is a shorter solution if your database support the standard WITH TIES clause:
select *
from yearly_product_revenue r
order by rank() over(partition by year order by revenue desc)
fetch first row with ties
I have a BigQuery table with this data
client spent balance date
A 20 500 2022-01-01
A 10 490 2022-01-02
A 50 440 2022-01-03
B 200 1000 1995-07-09
B 300 700 1998-08-11
B 100 600 2002-04-17
C 2 100 2021-01-04
C 10 90 2021-06-06
C 70 20 2021-10-07
I need the latest balance of each client based on the date:
client spent balance date
A 50 440 2022-01-03
B 100 600 2002-04-17
C 70 20 2021-10-07
distinct does not work like in sql and group on client does also not work because I need count, sum, etc. with the other columns when I use group.
For just one client I use:
SELECT balance FROM `table` WHERE client = "A" ORDER BY date DESC LIMIT 1.
But how can I get this data for every client in just one statement.
I tried with subselect
SELECT client,
(SELECT balance FROM ` table ` WHERE client = tb. client ORDER by date DESC limit 1) AS bal
FROM `table` AS tb;
and got the error:
Correlated subqueries that reference other tables are not supported
unless they can be de-correlated, such as by transforming them into an
efficient JOIN.
I don’t know how to make a JOIN out of this subquery to make it work.
Hope you have an idea.
Use below
select * from your_table
qualify 1 = row_number() over(partition by client order by date desc)
if applied to sample data in your question - output is
have you tried using row_number window function?
select client, spent, balance, date
from (
select client, spent, balance, date
, ROW_NUMBER() OVER (PARTITION BY client ORDER BY date DESC) AS row_num -- adding row number, starting from latest date
from table
)
where row_num = 1 -- filter out only the latest date
I have a table in Teradata which contains Sales Information per store pertaining to each region.
StoreID RegionID Sales
1 A 200
2 A 150
3 A 210
4 B 400
5 B 420
How can I find out the stores in top 2 deciles by sales for each region?
There's the QUANTILE function, but this is old deprecated syntax. The top 2 decile are the top 20 percent and you can simply use PERCENT_RANK for this:
QUALIFY
PERCENT_RANK()
OVER (PARTITION BY RegionID
ORDER BY Sales DESC) <= 0.2
I have 4 tables like this (you can ignore table B because this problem did not use that table)
I want to show the sum of 'total' for each 'sales_id' from table 'sales_detail'
What I want (the result) is like this:
sales_id | total
S01 | 3
S02 | 2
S03 | 4
S04 | 1
S05 | 2
S05 | 3
I have tried with this query:
select
sum(total)
from
sales_detail
where
sales_id = any (select sales_id
from sales
where customer_id = any (select customer_id
from customer)
)
but the query returns a value if 15 because they are the sum of those rows of data.
I have tried to use "distinct" before sum
and the result is [ 1, 2, 3 ] because those are distinct of those rows of data (not sum of each sales_id)
It's all about subquery
You are just so far off track that a simple comment won't help. Your query only concerns one table, sales_detail. It has nothing to do with the other two.
And, it is just an aggregation query:
select sd.sales_id, sum(sd.total)
from sales_detail sd
group by sd.sales_id;
This is actually pretty close to what the question itself is asking.
I am facing a very common issue regarding "Selecting top N rows for each group in a table".
Consider a table with id, name, hair_colour, score columns.
I want a resultset such that, for each hair colour, get me top 3 scorer names.
To solve this i got exactly what i need on Rick Osborne's blogpost "sql-getting-top-n-rows-for-a-grouped-query"
That solution doesn't work as expected when my scores are equal.
In above example the result as follow.
id name hair score ranknum
---------------------------------
12 Kit Blonde 10 1
9 Becca Blonde 9 2
8 Katie Blonde 8 3
3 Sarah Brunette 10 1
4 Deborah Brunette 9 2 - ------- - - > if
1 Kim Brunette 8 3
Consider the row 4 Deborah Brunette 9 2. If this also has same score (10) same as Sarah, then ranknum will be 2,2,3 for "Brunette" type of hair.
What's the solution to this?
If you're using SQL Server 2005 or newer, you can use the ranking functions and a CTE to achieve this:
;WITH HairColors AS
(SELECT id, name, hair, score,
ROW_NUMBER() OVER(PARTITION BY hair ORDER BY score DESC) as 'RowNum'
)
SELECT id, name, hair, score
FROM HairColors
WHERE RowNum <= 3
This CTE will "partition" your data by the value of the hair column, and each partition is then order by score (descending) and gets a row number; the highest score for each partition is 1, then 2 etc.
So if you want to the TOP 3 of each group, select only those rows from the CTE that have a RowNum of 3 or less (1, 2, 3) --> there you go!
The way the algorithm comes up with the rank, is to count the number of rows in the cross-product with a score equal to or greater than the girl in question, in order to generate rank. Hence in the problem case you're talking about, Sarah's grid would look like
a.name | a.score | b.name | b.score
-------+---------+---------+--------
Sarah | 9 | Sarah | 9
Sarah | 9 | Deborah | 9
and similarly for Deborah, which is why both girls get a rank of 2 here.
The problem is that when there's a tie, all girls take the lowest value in the tied range due to this count, when you'd want them to take the highest value instead. I think a simple change can fix this:
Instead of a greater-than-or-equal comparison, use a strict greater-than comparison to count the number of girls who are strictly better. Then, add one to that and you have your rank (which will deal with ties as appropriate). So the inner select would be:
SELECT a.id, COUNT(*) + 1 AS ranknum
FROM girl AS a
INNER JOIN girl AS b ON (a.hair = b.hair) AND (a.score < b.score)
GROUP BY a.id
HAVING COUNT(*) <= 3
Can anyone see any problems with this approach that have escaped my notice?
Use this compound select which handles OP problem properly
SELECT g.* FROM girls as g
WHERE g.score > IFNULL( (SELECT g2.score FROM girls as g2
WHERE g.hair=g2.hair ORDER BY g2.score DESC LIMIT 3,1), 0)
Note that you need to use IFNULL here to handle case when table girls has less rows for some type of hair then we want to see in sql answer (in OP case it is 3 items).