How do I implement the 'meaning' of the following psuedo-SQL statement:
COUNT(distinct id where attribute1 > 0)
In other words, how do I make conditional, distinct counting statements?
Thanks!
Well, if you can filter the entire query, then LittleBobbyTables already has the answer for you. If not, you can get that column like so:
count(distinct case when attribute1 > 0 then id end) -- implicit null-else, iirc
You pretty much had it:
SELECT COUNT(DISTINCT [ID]) AS DistinctID
FROM YourTable
WHERE attribute1 > 0
Related
Supposing I have this data. How to query this in such a way that will result to this in an efficient way. It will sum the qty of all OUT less the IN per item.
Try this query:
select
"Desc",
sum(case when Type = 'out' then Qty else 0 end) -
sum(case when Type = 'in' then Qty else 0 end)
from yourTable
group by "Desc"
Desc
Note that DESC is a reserved keyword and you should not be naming your databases, tables, or columns using it. I think you would have to escape it in double quotes to get the query to run.
select desc, sum(case Type when 'out' then Qty else -Qty end) from test group by desc;
this will be faster.
Or
SELECT Description, SUM(Case WHEN rowtype = 'in' then 1 else -1 end * Qty) as rowqty FROM yourtable GROUP BY description
Note that it is not a good idea to use reserved words as column names. DESC and TYPE are asking for trouble!
Using ms-sql 2008 r2; am sure this is very straightforward. I am trying to identify where a unique value {ISIN} has been linked to more than 1 Identifier. An example output would be:
isin entity_id
XS0276697439 000BYT-E
XS0276697439 000BYV-E
This is actually an error and I want to look for other instances where there may be more than one entity_id linked to a unique ISIN.
This is my current working but it's obviously not correct:
select isin, entity_id from edm_security_entity_map
where isin is not null
--and isin = ('XS0276697439')
group by isin, entity_id
having COUNT(entity_id) > 1
order by isin asc
Thanks for your help.
Elliot,
I don't have a copy of SQL in front of me right now, so apologies if my syntax isn't spot on.
I'd start by finding the duplicates:
select
x.isin
,count(*)
from edm_security_entity_map as x
group by x.isin
having count(*) > 1
Then join that back to the full table to find where those duplicates come from:
;with DuplicateList as
(
select
x.isin
--,count(*) -- not used elsewhere
from edm_security_entity_map as x
group by x.isin
having count(*) > 1
)
select
map.isin
,map.entity_id
from edm_security_entity_map as map
inner join DuplicateList as dup
on dup.isin = map.isin;
HTH,
Michael
So you're saying that if isin-1 has a row for both entity-1 and entity-2 that's an error but isin-3, say, linked to entity-3 in two separe rows is OK? The ugly-but-readable solution to that is to pre-pend another CTE on the previous solution
;with UniqueValues as
(select distinct
y.isin
,y.entity_id
from edm_security_entity_map as y
)
,DuplicateList as
(
select
x.isin
--,count(*) -- not used elsewhere
from UniqueValues as x
group by x.isin
having count(*) > 1
)
select
map.isin
,map.entity_id
from edm_security_entity_map as map -- or from UniqueValues, depening on your objective.
inner join DuplicateList as dup
on dup.isin = map.isin;
There are better solutions with additional GROUP BY clauses in the final query. If this is going into production I'd be recommending that. Or if your table has a bajillion rows. If you just need to do some analysis the above should suffice, I hope.
The query below returns 9,817 records. Now, I want to SELECT one more field from another table. See the 2 lines that are commented out, where I've simply selected this additional field and added a JOIN statement to bind this new columns. With these lines added, the query now returns 649,200 records and I can't figure out why! I guess something is wrong with my WHERE criteria in conjunction with the JOIN statement. Please help, thanks.
SELECT DISTINCT dbo.IMPORT_DOCUMENTS.ITEMID, BEGDOC, BATCHID
--, dbo.CATEGORY_COLLECTION_CATEGORY_RESULTS.CATEGORY_ID
FROM IMPORT_DOCUMENTS
--JOIN dbo.CATEGORY_COLLECTION_CATEGORY_RESULTS ON
dbo.CATEGORY_COLLECTION_CATEGORY_RESULTS.ITEMID = dbo.IMPORT_DOCUMENTS.ITEMID
WHERE (BATCHID LIKE 'IC0%' OR BATCHID LIKE 'LP0%')
AND dbo.IMPORT_DOCUMENTS.ITEMID IN
(SELECT dbo.CATEGORY_COLLECTION_CATEGORY_RESULTS.ITEMID FROM
CATEGORY_COLLECTION_CATEGORY_RESULTS
WHERE SCORE >= .7 AND SCORE <= .75 AND CATEGORY_ID IN(
SELECT CATEGORY_ID FROM CATEGORY_COLLECTION_CATS WHERE COLLECTION_ID IN (11,16))
AND Sample_Id > 0)
AND dbo.IMPORT_DOCUMENTS.ITEMID NOT IN
(SELECT ASSIGNMENT_FOLDER_DOCUMENTS.Item_Id FROM ASSIGNMENT_FOLDER_DOCUMENTS)
One possible reason is because one of your tables contains data at lower level, lower than your join key. For example, there may be multiple records per item id. The same item id is repeated X number of times. I would fix the query like the below. Without data knowledge, Try running the below modified query.... If output is not what you're looking for, convert it into SELECT Within a Select...
Hope this helps....
Try this SQL: SELECT DISTINCT a.ITEMID, a.BEGDOC, a.BATCHID, b.CATEGORY_ID FROM IMPORT_DOCUMENTS a JOIN (SELECT DISTINCT ITEMID FROM CATEGORY_COLLECTION_CATEGORY_RESULTS WHERE SCORE >= .7 AND SCORE <= .75 AND CATEGORY_ID IN (SELECT DISTINCT CATEGORY_ID FROM CATEGORY_COLLECTION_CATS WHERE COLLECTION_ID IN (11,16)) AND Sample_Id > 0) B ON a.ITEMID =b.ITEMID WHERE a.(a.BATCHID LIKE 'IC0%' OR a.BATCHID LIKE 'LP0%') AND a.ITEMID NOT IN (SELECT DIDTINCT Item_Id FROM ASSIGNMENT_FOLDER_DOCUMENTS)
I would like to do something like this:
CNT=2;
//[edit]
select avg(price) from (
select first :CNT p.Price
from Price p
order by p.Date desc
);
This does not work, Firebird does not allow :cnt as a parameter to FIRST. I need to average the first CNT newest prices. The number 2 changes so it can not be hard-coded.
This can be broken out into a FOR SELECT loop and break when a count is reached. Is that the best way though? Can this be done in a single SQL statement?
Creating the SQL as a string and running it is not the best fit either. It is important that the database compile my SQL statement.
You don't have to use CTE, you can do it directly:
select avg(price) from (
select first :cnt p.Price
from Price p
order by p.Date desc
);
You can use a CTE (Common Table Expression) (see http://www.firebirdsql.org/refdocs/langrefupd21-select.html#langrefupd21-select-cte) to select data before calculate average.
See example below:
with query1 as (
select first 2 p.Price
from Price p
order by p.Date desc
)
select avg(price) from query1
given a query like so:
SELECT
id,
(SELECT COUNT(*)
FROM members
WHERE members.network_id = networks.id) AS mem_count
FROM
networks
WHERE mem_count > 2
With this query, the where clause breaks as it does not know what mem_count is... Why can't I use the as var in the where clause?
Thanks
While bernie suggested correct answer to the question, your query can be simplified to:
SELECT
network_id as id,
count(*)
FROM
members
GROUP BY
network_id
HAVING
count(*) > 2
Which, as an additional bonus, can be faster.
You've got the concept down. You just need the right syntax. You could re-write like this and have the added benefit of making your query ANSI-compliant:
SELECT
id,
m.mem_count
FROM
networks n
JOIN (
SELECT m.network_id,
COUNT(*) AS mem_count
FROM members
GROUP BY m.network_id
) m
ON m.network_id = n.id
AND m.mem_count > 2;
Try:
SELECT
id,
(SELECT COUNT(*) as mem_count
FROM members
WHERE members.network_id = networks.id)
FROM
networks
WHERE mem_count > 2
One way would be.
Select * From (
SELECT
id,
(SELECT COUNT(*)
FROM members
WHERE members.network_id = networks.id) AS mem_count
FROM
networks)) mem_counts
WHERE mem_count > 2
A join as suggested by Bernie would be better though. Basically you confused the parser. You get the same sort of issue with group by or order by when you use AS to alias a column name.