SELECT
Rooms.Building,
Count(Rooms.Room) AS TotalApartments,
Count(Rooms.Room) AS ApartmentsOccupied
FROM
Rooms
WHERE
(((Rooms.AssetType) <> 'LC'))
GROUP BY
Rooms.Building;
I want to count Rooms.Room Where Rooms.Occupied = True (ApartmentsOccupied) but when I put this clause into my sql it also applies the where to the TotalApartments column
You can move some logic into CASE statements to do conditional summarization:
SELECT
Rooms.Building,
Count(Rooms.Room) AS TotalApartments,
Sum(CASE WHEN Rooms.Occupied = True THEN 1 ELSE 0 END) AS ApartmentsOccupied
FROM
Rooms
WHERE
(((Rooms.AssetType) <> 'LC'))
GROUP BY
Rooms.Building;
I'm not sure off the top of my head, but you might need to change that count to a SUM as well:
Sum(1) AS TotalApartments
And alternately, in some sql dialects the 'True' value is 1, so you could get away with something like this for the occupied count:
Sum(Rooms.Occupied) AS ApartmentsOccupied
You can do like this
SELECT
Building,
Count(Room) AS TotalApartments,
SUM(CASE WHEN Occupied = True THEN 1 ELSE 0 END) AS ApartmentsOccupied
FROM
Rooms
WHERE
AssetType <> 'LC'
GROUP BY
Building;
Related
I'm working to solve
https://platform.stratascratch.com/coding/10065-find-whether-the-number-of-seniors-works-at-facebook-is-higher-than-its-number-of-usa-based-employees?python=
This is the query I've attempted to write:
SELECT CASE WHEN COUNT(CASE WHEN location = 'US' THEN 1 ELSE 0 END) >
COUNT(CASE WHEN is_senior = true THEN 1 ELSE 0 END) THEN 'More USA-based'
ELSE 'More seniors' END AS what_do_we_have_more_of
FROM facebook_employees
Result: 'More seniors'
However, when I rewrite it with the conditions flipped around:
SELECT CASE WHEN COUNT(CASE WHEN is_senior = true THEN 1 ELSE 0 END) >
COUNT(CASE WHEN location = 'US' THEN 1 ELSE 0 END) THEN 'More seniors'
ELSE 'More USA-based' END AS what_do_we_have_more_of
FROM facebook_employees
Result: 'More USA-based'
Can someone please explain why there is a discrepancy here? What is wrong with the query I've written?
I know this problem can be solved with sub-queries but I wanted to try out a CASE WHEN approach specifically. Is this more efficient?
Edit: the solution I wrote with sub-queries (works with conditions reversed)
WITH us_employees AS (
SELECT id, location
FROM facebook_employees
WHERE location = 'US'
),
senior_employees AS (
SELECT id, is_senior
FROM facebook_employees
WHERE is_senior = true
)
SELECT CASE WHEN COUNT(location) < COUNT(is_senior) THEN 'More seniors' ELSE 'More US-based' END AS what_do_we_have_more_of
FROM us_employees u
FULL JOIN senior_employees s
ON u.id = s.id
Result: 'More seniors'
The use of count() in your query is incorrect. But how do you get different results? Because both counts are the same. So A > B is always false, and you always end up in the ELSE branch.
A proper query could look like this:
SELECT CASE WHEN count(*) FILTER (WHERE location = 'US')
> count(*) FILTER (WHERE is_senior) THEN 'More USA-based'
WHEN count(*) FILTER (WHERE location = 'US')
< count(*) FILTER (WHERE is_senior) THEN 'More seniors'
ELSE 'US-based and seniors tie' END AS what_do_we_have_more_of
FROM facebook_employees;
See:
Aggregate columns with additional (distinct) filters
Note, this can never fail with NULL values, because count() (unlike most aggregate functions) never returns NULL.
You should use SUM instead of COUNT.
COUNT will count +1 even when your CASE return 1 or 0.
SUM only count +1 when your CASE return 1.
So assume that your table has 1000 rows, then both your two queries will be CASE 1000 > 1000 THEN ... ELSE... END.
I have a column MessageId and have to take the count of distinct MessageId and if the result is 1, then have to display count as 0 else the count value itself. If the data set is more, using distinct twice is going to be a bit more time consuming.
...
CASE
WHEN count(DISTINCT MessageId) = 1
THEN 0
ELSE count(DISTINCT MessageId)
END as Count
...
Is there anyway to use COUNT(DISTINCT) only once using a single query itself? And also don't want to use multiple queries like assigning it to a variable and then using it.
Here is one method:
COALESCE(NULLIF(COUNT(DISTINCT MessageId), 1), 0)
it seems you need below
case when sum( case when MessageId= 1 then 1 else 0 end) =1
then 0 else
count(DISTINCT MessageId) end as cnt
I actually have a query joining 3 tables to collect informations so I can calculate some KPIs, but my logic is flawed, here is my actual query :
SELECT t.idCustomer, t.nameCustomer
COUNT(DISTINCT t.idTrip),
SUM(
CASE
WHEN t.tripDone <> 1
THEN 1
ELSE 0
END),
SUM(CASE
WHEN t.codeIncident = 'CANCEL'
THEN 1
ELSE 0
END)
FROM
(SELECT customer.idCustomer, customer.nameCustomer, trip.tripDone, incident.codeIncident
FROM CUSTOMER customer
JOIN TRIP trip ON customer.idCustomer = trip.idCustomer
JOIN INCIDENT incident ON trip.idTrip = incident.idTrip) t
GROUP BY t.idCustomer, t.nameCustomer
So, I want to know for each Customer :
COUNT(DISTINCT t.idTrip) -> The number of trips by this customer
Sum when t.tripDone <> 1 -> The number of trips that are done by this customer ( not ingoing )
Sum when t.codeIncident = 'CANCEL' -> The number of trips by this customer where there was a cancellation.
The big mistake I made here, is that a trip can have multiple codeIncidents (example : one record for an idTrip with the codeIncident 'CANCEL' and another record with same idTrip with the codeIncident 'DELAYED'), so when I calculate the Sum when t.tripDone <> 1 I get a result of : '2' instead of '1' (because there are 2 records in my from Clause that have the t.tripDone <> 1 for the same idTrip).
Would you have any idea on how I should process this query so I can do the Sum when tripDone <> 1 only once for each tripId ?
Thanks a lot for the help !
If you need some more infos I'm available, and sorry for my lack of english skills !
It sounds like you want to do the same count(distinct ...) pattern for the columns you're currently summing, but with some logic. You can use case within a count instead in the same way:
...
COUNT(
DISTINCT CASE
WHEN t.tripDone <> 1
THEN t.idTrip
ELSE null
END),
COUNT(
DISTINCT CASE
WHEN t.codeIncident = 'CANCEL'
THEN t.idTrip
ELSE null
END)
The else null is a bit redundant as that's the default. As count() ignores nulls, if the when isn't matched then that trip ID isn't counted.
First Select idTrip field in your inner query that means table "t"
SELECT round(COUNT(dmd_1wk),2) AS NBR_ITEMS_1WK
FROM table;
Field dmd_1wk has so many zeros in it. How do I Count the non zero values?
It sounds like you just need to add a WHERE clause:
SELECT
round(COUNT(dmd_1wk),2) AS NBR_ITEMS_1WK
FROM table
WHERE dmd_1wk <> 0;
If you want the count of both non-zero and zero values, then you can use something like:
SELECT
round(COUNT(case when dmd_1wk <> 0 then dmd_1wk end),2) AS NBR_ITEMS_1WK_NonZero,
round(COUNT(case when dmd_1wk = 0 then dmd_1wk end),2) AS NBR_ITEMS_1WK_Zero
FROM table;
Method 1: Case Statement. This may be useful if you need to continue to process all rows (which a where clause would prevent).
SELECT count(case when dmd_1wk = 0 then 0 else 1 end) as NonZeroCount FROM MyTable
Method 2: Where Clause.
SELECT
count(1) as NonZeroCount
FROM
MyTable
WHERE
dmd_1wk <> 0
I'd like to offer another solution using NULLIF since COUNT won't count NULL values:
SELECT round(COUNT(NULLIF(dmd_1wk,0)),2) AS NBR_ITEMS_1WK
FROM table;
And here is the Fiddle.
Good luck.
Methinks bluefeets answer is probably what you are really looking for, as it sounds like you just want to count non-zeros; but this will get you a count of zero and non-zero items if that's not the case:
SELECT
ROUND(SUM(CASE NVL(dmd_1wk, 0) = 0 THEN 1 ELSE 0 END), 2) AS "Zeros",
ROUND(SUM(CASE NVL(dmd_1wk, 0) != 0 THEN 1 ELSE 0 END), 2) AS "NonZeros"
FROM table
Although there is no point in rounding a whole number, I've included your original ROUNDs as I'm guessing you're using it for formatting, but you might want to use:
TO_CHAR(SUM(...), '999.00')
as that's the intended function for formatting numbers.
You can filter them.
SELECT round(COUNT(dmd_1wk),2) AS NBR_ITEMS_1WK
FROM table
WHERE dmd_1wk <> 0;
I want to add some calculation inside my case statement to dynamically create the contents of a new column but I get the error:
Column 'Test1.qrank' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.
This is the code I'm working on
case
when test1.TotalType = 'Average' then Test2.avgscore
when test1.TotalType = 'PercentOfTot' then (cnt/SUM(test1.qrank))
else cnt
end as displayscore
I did try to group but it didn't work.
Any hints?
The error you posted can happen when you're using a clause in the GROUP BY statement without including it in the select.
Example
This one works!
SELECT t.device,
SUM(case when transits.direction = 1 then 1 else 0 end) ,
SUM(case when transits.direction = 0 then 1 else 0 end) from t1 t
where t.device in ('A','B') group by t.device
This one not (omitted t.device from the select)
SELECT
SUM(case when transits.direction = 1 then 1 else 0 end) ,
SUM(case when transits.direction = 0 then 1 else 0 end) from t1 t
where t.device in ('A','B') group by t.device
This will produce your error complaining that I'm grouping for something that is not included in the select
Please, provide all the query to get more support.
You could use a Common Table Expression to create the SUM first, join it to the table, and then use the WHEN to to get the value from the CTE or the original table as necessary.
WITH PercentageOfTotal (Id, Percentage)
AS
(
SELECT Id, (cnt / SUM(AreaId)) FROM dbo.MyTable GROUP BY Id
)
SELECT
CASE
WHEN o.TotalType = 'Average' THEN r.avgscore
WHEN o.TotalType = 'PercentOfTot' THEN pt.Percentage
ELSE o.cnt
END AS [displayscore]
FROM PercentageOfTotal pt
JOIN dbo.MyTable t ON pt.Id = t.Id
If you're using SQL Server 2005 or above, you can use the windowing function SUM() OVER ().
case
when test1.TotalType = 'Average' then Test2.avgscore
when test1.TotalType = 'PercentOfTot' then (cnt/SUM(test1.qrank) over ())
else cnt
end as displayscore
But it'll be better if you show your full query to get context of what you actually need.