Having some trouble with some SQL.
Take the following result for instance:
LOC_CODE CHANNEL
------------ --------------------
3ATEST-01 CHAN2
3ATEST-01 CHAN3
3ATEST-02 CHAN4
What I need to do is get a count of the above query, grouped by channel, but i want that count to be divided by the count that the "LOC_CODE" appears.
Example of the result I am after is:
CHANNEL COUNT
---------------- ----------
CHAN2 0.5
CHAN3 0.5
CHAN4 1
Above explaination is that the CHAN2 appears next to "3ATEST-01", but that LOC_CODE of "3ATEST-01" appears twice, so the count should be divided by 2.
I know I can do this by basically duplicating the query with a distinct count, but the underlying query is quite complex and don't really want to harm performance.
Please let me know if you would like more information!
Try:
select channel,
count(*) over (partition by channel, loc_code)
/ count(*) over (partition by loc_code) as count_ratio
from my_table
SELECT t.CHANNEL, COUNT(*) / gr.TotalCount
FROM my_table t JOIN (
SELECT LOC_CODE, COUNT(*) TotalCount
FROM my_table
GROUP BY LOC_CODE
) gr USING(LOC_CODE)
GROUP BY t.LOC_CODE, t.CHANNEL
Create a index on (LOC_CODE, CHANNEL)
If are no duplicate channels, replace COUNT(*) / gr.TotalCount with 1 / gr.TotalCount and remove the GROUP BY clause
First, find a query that gets you the correct results. Then, see if it can be optimised. My guess is that it's hard to optimise as you require two different groupings, one per Channel and one pre Loc_Code.
I'm not even sure that this fits your description:
SELECT t.CHANNEL
, COUNT(*) / SUM(grp.TotalCount)
FROM my_table t
JOIN
( SELECT LOC_CODE
, COUNT(*) TotalCount --- or is it perhaps?:
--- COUNT(DISTINCT CHANNEL)
FROM my_table
GROUP BY LOC_CODE
) grp
ON grp.LOC_CODE = t.LOC_CODE
GROUP BY t.CHANNEL
Your requirements are still a bit unclear to me when it comes to duplicate CHANNELs, but this should work if you want grouping on both CHANNEL and LOC_CODE to sum up later;
SELECT L1.CHANNEL, 1/COUNT(L2.LOC_CODE)
FROM Locations L1
LEFT JOIN Locations L2 ON L1.LOC_CODE = L2.LOC_CODE
GROUP BY L1.CHANNEL, L1.LOC_CODE
Demo here.
Related
I am working on some car accident data and am stuck on how to get the data in the form I want.
select
sex_of_driver,
accident_severity,
count(accident_severity) over (partition by sex_of_driver, accident_severity)
from
SQL.dbo.accident as accident
inner join SQL.dbo.vehicle as vehicle on
accident.accident_index = vehicle.accident_index
This is my code, which counts the accidents had per each sex for each severity. I know I can do this with group by but I wanted to use a partition by in order to work out % too.
However I get a very large table (I assume for each row that is each sex/severity. When I do the following:
select
sex_of_driver,
accident_severity,
count(accident_severity) over (partition by sex_of_driver, accident_severity)
from
SQL.dbo.accident as accident
inner join SQL.dbo.vehicle as vehicle on
accident.accident_index = vehicle.accident_index
group by
sex_of_driver,
accident_severity
I get this:
sex_of_driver
accident_severity
(No column name)
1
1
1
1
2
1
-1
2
1
-1
1
1
1
3
1
I won't give you the whole table, but basically, the group by has caused the count to just be 1.
I can't figure out why group by isn't working. Is this an MS SQL-Server thing?
I want to get the same result as below (obv without the CASE etc)
select
accident.accident_severity,
count(accident.accident_severity) as num_accidents,
vehicle.sex_of_driver,
CASE vehicle.sex_of_driver WHEN '1' THEN 'Male' WHEN '2' THEN 'Female' end as sex_col,
CASE accident.accident_severity WHEN '1' THEN 'Fatal' WHEN '2' THEN 'Serious' WHEN '3' THEN 'Slight' end as serious_col
from
SQL.dbo.accident as accident
inner join SQL.dbo.vehicle as vehicle on
accident.accident_index = vehicle.accident_index
where
sex_of_driver != 3
and
sex_of_driver != -1
group by
accident.accident_severity,
vehicle.sex_of_driver
order by
accident.accident_severity
You seem to have a misunderstanding here.
GROUP BY will reduce your rows to a single row per grouping (ie per pair of sex_of_driver, accident_severity values. Any normal aggregates you use with this, such as COUNT(*), will return the aggregate value within that group.
Whereas OVER gives you a windowed aggregated, and means you are calculating it after reducing your rows. Therefore when you write count(accident_severity) over (partition by sex_of_driver, accident_severity) the aggregate only receives a single row in each partition, because the rows have already been reduced.
You say "I know I can do this with group by but I wanted to use a partition by in order to work out % too." but you are misunderstanding how to do that. You don't need PARTITION BY to work out percentage. All you need to calculate a percentage over the whole resultset is COUNT(*) * 1.0 / SUM(COUNT(*)) OVER (), in other words a windowed aggregate over a normal aggregate.
Note also that count(accident_severity) does not give you the number of distinct accident_severity values, it gives you the number of non-null values, which is probably not what you intend. You also have a very strange join predicate, you probably want something like a.vehicle_id = v.vehicle_id
So you want something like this:
select
sex_of_driver,
accident_severity,
count(*) as Count,
count(*) * 1.0 /
sum(count(*)) over (partition by sex_of_driver) as PercentOfSex
count(*) * 1.0 /
sum(count(*)) over () as PercentOfTotal
from
dbo.accident as accident a
inner join dbo.vehicle as v on
a.vehicle_id = v.vehicle_id
group by
sex_of_driver,
accident_severity;
When i run this query
SELECT
DT.CONTRACT_NUMBER,
DT.ROLE,
DT.TAX_ID,
DT.EFFECTIVE_DATE
FROM DATA_TABLE DT
I get this result.
Id like to remove results where the TAX ID appears more than once for each contract.
i.e This result would be gone. If they had 3 results they would be gone.
I think window functions might be the way to go:
SELECT DT.CONTRACT_NUMBER, DT.ROLE, DT.TAX_ID, DT.EFFECTIVE_DATE
FROM (SELECT DT.CONTRACT_NUMBER, DT.ROLE, DT.TAX_ID, DT.EFFECTIVE_DATE,
COUNT(*) OVER (PARTITION BY TAX_ID) as cnt
FROM DATA_TABLE DT
WHERE DT.CONTRACT_NUMBER = '551000280'
) DT
WHERE CNT = 1;
If you actually want to keep one row per tax id, then use row_number() instead of count(*).
I have a block of data which has duplicate row ID's (CLIENT_DIWOR is the ROW ID) but relate to different groups. I can't just delete the duplicate row as they tie in to two different groups, so what I am trying to do is move the duplicate to the next column, so I can get the calculations correct at the end of my query. So for an example of what I am after
This is what I have
CLIENT_DIWOR GROUP_NAME
-1 Priv Client Serv (Sector)
-1 Social Business (Sector)
This is what I want
CLIENT_DIWOR GROUP_NAME Second Group Name
-1 Priv Client Serv (Sector) Social Business (Sector)
I have tried using COUNT(*) with a group by but that doesn't bring the correct results as it will just tell me there are 1 of everything, and what I am after is every time client_DIWOR duplicates add 1 to the previous number, as that will give me what I need to separate them out and rebuild it into a table, but I just cant see how to count it without grouping the numbers together, this is what I have so far with the count removed as I know that is wrong.
SELECT A.CLIENT_DIWOR,B.GROUP_NAME
from CLIENT_GRP_MEMBER A
JOIN CLIENT_GROUP B on B.DIWOR = A.CLIENT_GRP_DIWOR
order by CLIENT_DIWOR
A more general solution, using ROW_NUMBER:
WITH cte AS (
SELECT *, ROW_NUMBER() OVER (PARTITION BY A.CLIENT_DIWOR ORDER BY B.GROUP_NAME) rn
FROM CLIENT_GRP_MEMBER A
INNER JOIN CLIENT_GROUP B
ON B.DIWOR = A.CLIENT_GRP_DIWOR
)
SELECT
CLIENT_DIWOR,
MAX(CASE WHEN rn = 1 THEN GROUP_NAME END) AS GROUP_NAME,
MAX(CASE WHEN rn = 2 THEN GROUP_NAME END) AS SECOND_GROUP_NAME
FROM cte
GROUP BY
CLIENT_DIWOR;
The advantage of this approach is that you ever need to cater to more than two columns in the output, you can easily extend the query.
If you want to put two groups for each CLIENT_DIWOR, you can use aggregation:
SELECT CLIENT_DIWOR,
MIN(GROUP_NAME) as GROUP_NAME
NULLIF(MAX(GROUP_NAME), MIN(GROUP_NAME)) as GROUP_NAME_2
from CLIENT_GRP_MEMBER cgm
GROUP BY CLIENT_DIWOR ;
Hi how can I get the percentage of each record over the total?
Lets imagine I have one table with the following
ID code Points
1 101 2
2 201 3
3 233 4
4 123 1
The percentage for ID 1 is 20% for 2 is 30% and so one
how do I get it?
There's a couple approaches to getting that result.
You essentially need the "total" points from the whole table (or whatever subset), and get that repeated on each row. Getting the percentage is a simple matter of arithmetic, the expression you use for that depends on the datatypes, and how you want that formatted.
Here's one way (out a couple possible ways) to get the specified result:
SELECT t.id
, t.code
, t.points
-- , s.tot_points
, ROUND(t.points * 100.0 / s.tot_points,1) AS percentage
FROM onetable t
CROSS
JOIN ( SELECT SUM(r.points) AS tot_points
FROM onetable r
) s
ORDER BY t.id
The view query s is run first, that gives a single row. The join operation matches that row with every row from t. And that gives us the values we need to calculate a percentage.
Another way to get this result, without using a join operation, is to use a subquery in the SELECT list to return the total.
Note that the join approach can be extended to get percentage for each "group" of records.
id type points %type
-- ---- ------ -----
1 sold 11 22%
2 sold 4 8%
3 sold 25 50%
4 bought 1 50%
5 bought 1 50%
6 sold 10 20%
To get that result, we can use the same query, but a a view query for s that returns total GROUP BY r.type, and then the join operation isn't a CROSS join, but a match based on type:
SELECT t.id
, t.type
, t.points
-- , s.tot_points_by_type
, ROUND(t.points * 100.0 / s.tot_points_by_type,1) AS `%type`
FROM onetable t
JOIN ( SELECT r.type
, SUM(r.points) AS tot_points
FROM onetable r
GROUP BY r.type
) s
ON s.type = t.type
ORDER BY t.id
To do that same result with the subquery, that's going to be a correlated subquery, and that subquery is likely to get executed for every row in t.
This is why it's more natural for me to use a join operation, rather than a subquery in the SELECT list... even when a subquery works the same. (The patterns we use for more complex queries, like assigning aliases to tables, qualifying all column references, and formatting the SQL... those patterns just work their way back into simple queries. The rationale for these patterns is kind of lost in simple queries.)
try like this
select id,code,points,(points * 100)/(select sum(points) from tabel1) from table1
To add to a good list of responses, this should be fast performance-wise, and rather easy to understand:
DECLARE #T TABLE (ID INT, code VARCHAR(256), Points INT)
INSERT INTO #T VALUES (1,'101',2), (2,'201',3),(3,'233',4), (4,'123',1)
;WITH CTE AS
(SELECT * FROM #T)
SELECT C.*, CAST(ROUND((C.Points/B.TOTAL)*100, 2) AS DEC(32,2)) [%_of_TOTAL]
FROM CTE C
JOIN (SELECT CAST(SUM(Points) AS DEC(32,2)) TOTAL FROM CTE) B ON 1=1
Just replace the table variable with your actual table inside the CTE.
I have a postgresql query like this:
with r as (
select
1 as reason_type_id,
rarreason as reason_id,
count(*) over() count_all
from
workorderlines
where
rarreason != 0
and finalinsdate >= '2012-12-01'
)
select
r.reason_id,
rt.desc,
count(r.reason_id) as num,
round((count(r.reason_id)::float / (select count(*) as total from r) * 100.0)::numeric, 2) as pct
from r
left outer join
rtreasons as rt
on
r.reason_id = rt.rtreason
and r.reason_type_id = rt.rtreasontype
group by
r.reason_id,
rt.desc
order by r.reason_id asc
This returns a table of results with 4 columns: the reason id, the description associated with that reason id, the number of entries having that reason id, and the percent of the total that number represents.
This table looks like this:
What I would like to do is only display the top 10 results based off the total number of entries having a reason id. However, whatever is leftover, I would like to compile into another row with a description called "Other". How would I do this?
with r2 as (
...everything before the select list...
dense_rank() over(order by pct) cause_rank
...the rest of your query...
)
select * from r2 where cause_rank < 11
union
select
NULL as reason_id,
'Other' as desc,
sum(r2.num) over() as num,
sum(r2.pct) over() as pct,
11 as cause_rank
from r2
where cause_rank >= 11
As said above Limit and for the skipping and getting the rest use offset... Try This Site
Not sure about Postgre but SELECT TOP 10... should do the trick if you sort correctly
However about the second part: You might use a Right Join for this. Join the TOP 10 Result with the whole table data and use only the records not appearing on the left side. If you calculate the sum of those you should get your "Sum of the rest" result.
I assume that vw_my_top_10 is the view showing you the top 10 records. vw_all_records shows all records (including the top 10).
Like this:
SELECT SUM(a_field)
FROM vw_my_top_10
RIGHT JOIN vw_all_records
ON (vw_my_top_10.Key = vw_all_records.Key)
WHERE vw_my_top_10.Key IS NULL