I have a data set that is being updated on each operation maden by customers.
For example, I am getting a customer's last two operations by
select id,
referance
from (select id,
referance,
row_number()
over (order by time desc) as seqnum
from mytable where id=':id')
al where seqnum <= 2
where id is getting from a feature file. But now I need to compare the referance values of these two operations.
mytable:
id | name | referance | time |
-------------------------------------
11 | abc | 4589 | 09:05 |
11 | abc | 1234 | 09:04 |
10 | xyz | 0185 | 09:02 |
15 | qpr | 9564 | 08:54 |
so on...
Again, I can get the last two rows with id = 11; and, as far as all columns are not (null), it is returning "true" which is what I want literally.
But also I'd like to compare if their referances are the same or not; and, when I call the query, it has to return "true" or "false".
Thanks in advance
P.S. I actually just need a useful function or idea. I've already try to use inner join but couldnt manage it:
select table1.id,
table1.referance,
table2.id,
table2.referance
from (select id,
referance,
row_number()
over (order by time desc) as seqnum
from mytable where id=':id') table1
inner join (select id,
referance,
row_number()
over (order by time desc) as seqnum
from mytable where id=':id') table2
on table1.referance != table2.referance
al where seqnum <= 2 order by seqnum
Aggregate your current query over the id and check if the two reference values be the same or not.
select
id,
case when count(distinct reference) = 1
then 'true' else 'false' end as result
from
(
select id, reference,
row_number() over (order by time desc) as seqnum
from table
where id=':id'
) al
where seqnum <= 2
group by id;
If the distinct count of reference over the two records be 1 then it implies that they have the same value. Otherwise, we can assume that the values are different.
Why are you using row_nubmer()? You can get the last two rows as:
select top 2 id, referance
from mytable
where id=':id'
order by time desc;
You can then determine if these are the same using aggregation:
select (case when min(reference) <> max(reference) then 'false'
else 'true'
end) as is_same
from (select top 2 id, referance
from mytable
where id=':id'
order by time desc
) t;
Note: This doesn't take NULL values for reference into account, but that is easily incorporated into the logic.
Related
If I have data like so:
+----+-------+
| id | value |
+----+-------+
| 1 | 10 |
| 1 | 10 |
| 2 | 20 |
| 3 | 30 |
| 2 | 20 |
+----+-------+
How do I calculate the average based on the distinct id WITHOUT using a subquery (i.e. querying the table directly)?
For the above example it would be (10+20+30)/3 = 20
I tried to do the following:
SELECT AVG(IF(id = LAG(id) OVER (ORDER BY id), NULL, value)) AS avg
FROM table
Basically I was thinking that if I order by id and check the previous row to see if it has the same id, the value should be NULL and thus it would not be counted into the calculation, but unfortunately I can't put analytical functions inside aggregate functions.
As far as I know, you can't do this without a subquery. I would use:
SELECT AVG(avg_value)
FROM
(
SELECT AVG(value) AS avg_value
FROM yourTable
GROUP BY id
) t;
WITH RANK AS (
Select *,
ROW_NUMBER() OVER(PARTITION BY ID) AS RANK
FROM
TABLE
QUALIFY RANK = 1
)
SELECT
AVG(VALUES)
FROM RANK
The outer query will have other parameters that need to access all the data in the table
I interpret this comment as wanting an average on every row -- rather than doing an aggregation. If so, you can use window functions:
select t.*,
avg(case when seqnum = 1 then value end) over () as overall_avg
from (select t.*,
row_number() over (partition by id order by id) as seqnum
from t
) t;
Yes there is a way,
Simply use distinct inside the avg function as below :
select avg(distinct value) from tab;
http://sqlfiddle.com/#!4/9d156/2/0
What I'm Looking for:
I need to have a list from SQL server getting all IDs, but each ID have multiples lines.
Some lines from each ID are systems update so do not need to take care about them in my query.
In another words:
I need to get the whole list, counting all lines that are not from system for each ID.
The Database its looks like below:
ID | linenumber| data, data, ... data|Requesto| data, data
1 | 1 |.....................|JUAN |...........
1 | 2 |.....................|SYSTEM |...........
2 | 1 |.....................|Matias |...........
2 | 2 |.....................|Matias |...........
2 | 3 |.....................|Matias |...........
And I need to get:
ID | CantRoWs |.....................|WHO is |...........
1 | 1 |.....................|JUAN |...........
2 | 3 |.....................|Matias |...........
I was thinking about using a temp query like below but it does not work.
with temp as
(
SELECT OVER (PARTITION BY szCID ORDER BY gdReceived desc) as RowNum,*
FROM TABLE1;
)
SELECT *, (Select count(szCID) from TABLE1 where szAccount <> 'system') AS Hits From temp
WHERE RowNum = 1
Any ideas?
I would suggest you start by using row_number() and count() inside the common table expression:
WITH temp
AS (
SELECT
*
, ROW_NUMBER() OVER (PARTITION BY szCID ORDER BY gdReceived DESC) AS RowNum
, COUNT(*) OVER (PARTITION BY szCID) as hits
FROM TABLE1
WHERE szAccount <> 'system'
)
SELECT
*
FROM temp
WHERE RowNum = 1
So say I have this table called Key_Values that looks like
--keys--|--values--
A | 1
A | 1
A | 2
B | 1
B | 1
C | 3
C | 3
C | 4
I need to write a single select statement that would get all of the distinct keys, and their respective values' mode. It would return this
--keys--|--values--
A | 1
B | 1
C | 3
I'm having some trouble figuring out the correct way to do this. I know I can do a DISTINCT(keys), but I'm not sure how to get the values from that.
You can use window functions if your database supports it:
select key, value as mode
from (select key, value, count(*) as cnt,
row_number() over (partition by key order by count(*) desc) as seqnum
from keyvalue
group by key, value
) kv
where seqnum = 1;
In MS Access, this is much more painful:
select key, value, count(*) as cnt
from keyvalue kv
group by key, value
having kv.value = (select top (1) kv2.value
from keyvalue kv2
where kv2.key = kv.key
group by kv2.value
order by count(*) desc
);
I have a table with, among other things, these columns: DateTransferred, ComputedQuantity, StoreID, ItemID
I have two goals. My simpler goal is to write a query where I feel in the ItemID and it sums up the ComputedQuantity where it matches that ItemID, only using the most recent DateTransferred for each StoreID. So with the following example data:
DateTransferred | StoreID | ItemID | ComputedQuantity
11/10/17 | 1 | 1 | 3 <
10/10/17 | 1 | 1 | 4
09/10/17 | 2 | 1 | 9 <
08/10/17 | 3 | 1 | 1 <
07/10/17 | 3 | 1 | 10
I would want it to pull every row with < next to it, as that's the most recent Date for that StoreID, and sum up to 13
My more complicated goal is that I would like to include the above-calculated value into a 'join' where I'm dealing with the Item table, so that I can pull all the items and join them with a new column which has the summed up ComputedQuantity
This is on SQL Server 10 on Windows Server 2008, if that matters
One simple method uses a correlated subquery:
select t.*
from t
where t. DateTransferred = (select max(t2.DateTransferred)
from t t2
where t2.storeid = t.storeid
);
Another even simpler method uses window functions:
select t.*
from (select t.*,
row_number() over (partition by storeid order by DateTransferred desc) as seqnum
from t
) t
where seqnum = 1;
In either case, you can add a where clause to the subquery if you want the most recent date on or before some given date (say a year ago).
Also, these both assume that your data has no future dates. If so, then add where DateTransferred < getdate().
The final statement which sums the ComputedQuantities:
select ItemID, SUM(ComputedQuantity) Quantity
from (select t.*,
row_number() over (partition by StoreID, ItemID order by DateTransferred DESC) as seqnum
from [db].[dbo].[InventoryTransferLog] t
) t
where seqnum = 1 and ComputedQuantity > 0
GROUP BY ItemID
ORDER BY ItemID
I decided not to sum values < 0
I don't really know how to describe it. I have a table:
ID | Name | Date
-------------------------
1 | Mike | 01.01.2016
1 | Michael | 02.03.2016
2 | Samuel | 23.12.2015
2 | Sam | 05.03.2015
3 | Tony | 02.04.2012
I want to select pairs of IDs and Names with latest dates in each pair. The result here should be:
ID | Name | Date
-------------------------
1 | Michael | 02.03.2016
2 | Samuel | 23.12.2015
3 | Tony | 02.04.2012
How do I achieve this?
Oracle Database 11g
You can do it using the ROW_NUMBER() analytic function:
SELECT id, name, "date"
FROM (
SELECT t.*,
ROW_NUMBER() OVER ( PARTITION BY id ORDER BY "date" DESC ) rn
FROM table_name t
)
WHERE rn = 1
This requires only a single table scan (it does not have a self-join or correlated sub-query - i.e. IN (...) or EXISTS(...)).
Have a sub-select that returns each id and it's max date:
select * from table
where (id, date) in (select id, max(date) from table group by id)
You can use NOT EXISTS() :
SELECT * FROM YourTable t
WHERE NOT EXISTS(SELECT 1 FROM YourTable s
WHERE t.id = s.id and s.date > t.date)
Possibly the most efficient method is:
select t.*
from table t
where t.date = (select max(date) from table t2 where t2.id = t.id);
along with an index on table(id, date).
This version should scan the table and look up the correct value in the index.
Or, if there are only three columns, you can use keep:
select id, max(date) as date,
max(name) keep (dense_rank first order by date desc) as name
from table
group by id;
I have found that this version works very well in Oracle.