I have a question about writing query in sql (in continue of my previous question: subtract values of two rows and inserting it into a new column (not subsequent rows)):
I want to write a query that calculate the number of times that a user had won a competition before the current time, the condition of winning is place=1 ; I want the result in a new column (win-frequency) and the value of [win-frequency] changes when a new winning happens. in the following picture, I calculated win-frequency manually.
http://www.8pic.ir/images/54691148512772358477.jpg
I write the following query, but I got error:
SELECT [user-name],
submissions,
[date],
place,
recency,
[win-recency],
COUNT( SELECT [date] FROM [top-design1]] td1
WHERE td1.[user-name] = [top-design1].[user-name]
AND place=1
AND [date]< [top-design1].[date]
ORDER BY [date] DESC) as win-frequency
)
FROM [top-design1]
this is the sql fiddle:
http://sqlfiddle.com/#!3/0ec5f
You have to fix the brackets ) and [, remove the ORDER BY from the correlated subquery, and escape the column name [win-frequency]. It should be this way:
SELECT [user-name],
submissions,
[date],
place,
recency,
[win-recency],
(SELECT COUNT([date])
FROM [top-design1] td1
WHERE td1.[user-name] = [top-design1].[user-name]
AND place = 1
AND [date] < [top-design1].[date]
) as [win-frequency]
FROM [top-design1];
Updated SQL Fiddle Demo.
Related
I have a question regarding the max-statement in a select -
Without the MAX-statemen i have this select:
SELECT stockID, DATE, close, symbol
FROM ta_stockprice JOIN ta_stock ON ta_stock.id = ta_stockprice.stockID
WHERE stockid = 8648
ORDER BY close
At the end i only want to have the max row for the close-column so i tried:
Why i didn´t get date = "2021-07-02" as output?
(i saw that i allways get "2021-07-01" as output - no matter if i use MAX / MIN / AVG...)
The MAX() turns the query into an aggregation query. With no GROUP BY, it returns one row. But the query is syntactically incorrect, because it mixes aggregated and unaggregated columns.
Once upon a time, MySQL allowed such syntax in violation of the SQL Standard but returned values from arbitrary rows for the unaggreged columns.
Use ORDER BY to do what you want:
SELECT stockID, DATE, close, symbol
FROM ta_stockprice JOIN ta_stock ON ta_stock.id = ta_stockprice.stockID
WHERE stockid = 8648
ORDER BY close DESC
LIMIT 1;
I have been trying to write a query to perfect this instance but cant seem to do the trick because I am still receiving duplicated. Hoping I can get help how to fix this issue.
SELECT DISTINCT
1.Client
1.ID
1.Thing
1.Status
MIN(1.StatusDate) as 'statdate'
FROM
SAMPLE 1
WHERE
[]
GROUP BY
1.Client
1.ID
1.Thing
1.status
My output is as follows
Client Id Thing Status Statdate
CompanyA 123 Thing1 Approved 12/9/2019
CompanyA 123 Thing1 Denied 12/6/2019
So although the query is doing what I asked and showing the mininmum status date per status, I want only the first status date. I have about 30k rows to filter through so whatever does not run overload the query and have it not run. Any help would be appreciated
Use window functions:
SELECT s.*
FROM (SELECT s.*,
ROW_NUMBER() OVER (PARTITION BY id ORDER BY statdate) as seqnum
FROM SAMPLE s
WHERE []
) s
WHERE seqnum = 1;
This returns the first row for each id.
Use whichever of these you feel more comfortable with/understand:
SELECT
*
FROM
(
SELECT *, ROW_NUMBER() OVER (PARTITION BY id ORDER BY statusdate) as rn
FROM sample
WHERE ...
) x
WHERE rn = 1
The way that one works is to number all rows sequentially in order of StatusDate, restarting the numbering from 1 every time ID changes. If you thus collect all the number 1's togetyher you have your set of "first records"
Or can coordinate a MIN:
SELECT
*
FROM
sample s
INNER JOIN
(SELECT ID, MIN(statusDate) as minDate FROM sample WHERE ... GROUP BY ID) mins
ON s.ID = mins.ID and s.StatusDate = mins.MinDate
WHERE
...
This one prepares a list of all the ID and the min date, then joins it back to the main table. You thus get all the data back that was lost during the grouping operation; you cannot simultaneously "keep data" and "throw away data" during a group; if you group by more than just ID, you get more groups (as you have found). If you only group by ID you lose the other columns. There isn't any way to say "GROUP BY id, AND take the MIN date, AND also take all the other data from the same row as the min date" without doing a "group by id, take min date, then join this data set back to the main dataset to get the other data for that min date". If you try and do it all in a single grouping you'll fail because you either have to group by more columns, or use aggregating functions for the other data in the SELECT, which mixes your data up; when groups are done, the concept of "other data from the same row" is gone
Be aware that this can return duplicate rows if two records have identical min dates. The ROW_NUMBER form doesn't return duplicated records but if two records have the same minimum StatusDate then which one you'll get is random. To force a specific one, ORDER BY more stuff so you can be sure which will end up with 1
I have a table with the following columns
id, timestamp, current load count, previous load count
and it has many rows. I have values for all the first three columns, but for the "previous load count", I need to get the count of the date one day before the count of the current load count.
See the below image (table example) to view the sample table
For example: previous load count of id:4 is the count same as the current load count of id:5.
Is there anyway to write a SQL statement to update the previous load count?
Can you try this?
SELECT [id]
,[timestamp]
,[current load count]
,LAG([current load count]) OVER (ORDER BY [timestamp] ASC, [id]) AS [previous load count]
FROM [table]
The LAG function can be used to access data from a previous row in the same result set without the use of a self-join.
It is available after SQL Server 2012.
In the example I added ordering by id, too - in case you have records with same date, but you can remove it if you like.
If you need exactly one day before, consider a join:
select t.*, tprev.load_count as prev_load_count
from t left join
t tprev
on tprev.timestamp = dateadd(day, -1, t.timestamp);
(Note: If the timestamp has a time component, you will need to convert to a date.)
lag() gives you the data from the previous row. If you know you have no gaps, then these are equivalent. However, if there are gaps, then this returns NULL on the days after the gap. That appears to be what you are asking for.
You can incorporate either this or lag() into an update:
update t
set prev_load_count = tprev.load_count
from t join
t tprev
on tprev.timestamp = dateadd(day, -1, t.timestamp);
I have a SQL statement that I am currently using to return a number of rows from a database:
SELECT
as1.AssetTagID, as1.TagID, as1.CategoryID,
as1.Description, as1.HomeLocationID, as1.ParentAssetTagID
FROM Assets AS as1
INNER JOIN AssetsReads AS ar ON as1.AssetTagID = ar.AssetTagID
WHERE
(ar.ReadPointLocationID='Readpoint1' OR ar.ReadPointLocationID='Readpoint2')
AND (ar.DateScanned between 'LastScan' AND 'Now')
AND as1.TagID!='000000000000000000000000'
I am wanting to do a query that will get the row with the oldest DateScanned from this query and also get another row from the database if there was one that was within a certain period of time from this row (say 5 seconds for an example). The oldest record would be relatively simple by selecting the first record in a descending sort, but how would I also get the second record if it was within a certain time period of the first?
I know I could do this process with multiple queries, but is there any way to combine this process into one query?
The database that I am using is SQL Server 2008 R2.
Also please note that the DateScanned times are just placeholders and I am taking care of that in the application that will be using this query.
Here is a fairly general way to approach it. Get the oldest scan date using min() as a window function, then use date arithmetic to get any rows you want:
select t.* -- or whatever fields you want
from (SELECT as1.AssetTagID, as1.TagID, as1.CategoryID,
as1.Description, as1.HomeLocationID, as1.ParentAssetTagID,
min(DateScanned) over () as minDateScanned, DateScanned
FROM Assets AS as1
INNER JOIN AssetsReads AS ar ON as1.AssetTagID = ar.AssetTagID
WHERE (ar.ReadPointLocationID='Readpoint1' OR ar.ReadPointLocationID='Readpoint2')
AND (ar.DateScanned between 'LastScan' AND 'Now')
AND as1.TagID!='000000000000000000000000'
) t
where datediff(second, minDateScanned, DateScanned) <= 5;
I am not really sure of sql server syntax, but you can do something like this
SELECT * FROM (
SELECT
TOP 2
as1.AssetTagID,
as1.TagID,
as1.CategoryID,
as1.Description,
as1.HomeLocationID,
as1.ParentAssetTagID ,
ar.DateScanned,
LAG(ar.DateScanned) OVER (order by ar.DateScanned desc) AS lagging
FROM
Assets AS as1
INNER JOIN AssetsReads AS ar
ON as1.AssetTagID = ar.AssetTagID
WHERE (ar.ReadPointLocationID='Readpoint1' OR ar.ReadPointLocationID='Readpoint2')
AND (ar.DateScanned between 'LastScan' AND 'Now')
AND as1.TagID!='000000000000000000000000'
ORDER BY
ar.DateScanned DESC
)
WHERE
lagging IS NULL or DateScanned - lagging < '5 SECONDS'
I have tried to sort the results by DateScanned desc and then just the top most 2 rows. I have then used the lag() function on DateScanned field, to get the DateScanned value for the previous row. For the topmost row the DateScanned shall be null as its the first record, but for the second one it shall be value of the first row. You can then compare both of these values to determine whether you wish to display the second row or not
more info on the lagging function: http://blog.sqlauthority.com/2011/11/15/sql-server-introduction-to-lead-and-lag-analytic-functions-introduced-in-sql-server-2012/
I have 2 similar queries which both work on the same table, and I essentially want to combine their results such that the second query supplies default values for what the first query doesn't return. I've simplified the problem as much as possible here. I'm using Oracle btw.
The table has account information in it for a number of accounts, and there are multiple entries for each account with a commit_date to tell when the account information was inserted. I need get the account info which was current for a certain date.
The queries take a list of account ids and a date.
Here is the query:
-- Select the row which was current for the accounts for the given date. (won't return anything for an account which didn't exist for the given date)
SELECT actr.*
FROM Account_Information actr
WHERE actr.account_id in (30000316, 30000350, 30000351)
AND actr.commit_date <= to_date( '2010-DEC-30','YYYY-MON-DD ')
AND actr.commit_date =
(
SELECT MAX(actrInner.commit_date)
FROM Account_Information actrInner
WHERE actrInner.account_id = actr.account_id
AND actrInner.commit_date <= to_date( '2010-DEC-30','YYYY-MON-DD ')
)
This looks a little ugly, but it returns a single row for each account which was current for the given date. The problem is that it doesn't return anything if the account didn't exist until after the given date.
Selecting the earliest account info for each account is trival - I don't need to supply a date for this one:
-- Select the earliest row for the accounts.
SELECT actr.*
FROM Account_Information actr
WHERE actr.account_id in (30000316, 30000350, 30000351)
AND actr.commit_date =
(
SELECT MAX(actrInner .commit_date)
FROM Account_Information actrInner
WHERE actrInner .account_id = actr.account_id
)
But I want to merge the result sets in such a way that:
For each account, if there is account info for it in the first result set - use that.
Otherwise, use the account info from the second result set.
I've researched all of the joins I can use without success. Unions almost do it but they will only merge for unique rows. I want to merge based on the account id in each row.
Sql Merging two result sets - my case is obviously more complicated than that
SQL to return a merged set of results - I might be able to adapt that technique? I'm a programmer being forced to write SQL and I can't quite follow that example well enough to see how I could modify it for what I need.
The standard way to do this is with a left outer join and coalesce. That is, your overall query will look like this:
SELECT ...
FROM defaultQuery
LEFT OUTER JOIN currentQuery ON ...
If you did a SELECT *, each row would correspond to the current account data plus your defaults. With me so far?
Now, instead of SELECT *, for each column you want to return, you do a COALESCE() on matched pairs of columns:
SELECT COALESCE(currentQuery.columnA, defaultQuery.columnA) ...
This will choose the current account data if present, otherwise it will choose the default data.
You can do this more directly using analytic functions:
select *
from (SELECT actr.*, max(commit_date) over (partition by account_id) as maxCommitDate,
max(case when commit_date <= to_date( '2010-DEC-30','YYYY-MON-DD ') then commit_date end) over
(partition by account_id) as MaxCommitDate2
FROM Account_Information actr
WHERE actr.account_id in (30000316, 30000350, 30000351)
) t
where (MaxCommitDate2 is not null and Commit_date = MaxCommitDate2) or
(MaxCommitDate2 is null and Commit_Date = MaxCommitDate)
The subquery calculates two values, the two possibilities of commit dates. The where clause then chooses the appropriate row, using the logic that you want.
I've combined the other answers. Tried it out at apex.oracle.com. Here's some explanation.
MAX(CASE WHEN commit_date <= to_date('2010-DEC-30', 'YYYY-MON-DD')) will give us the latest date not before Dec 30th, or NULL if there isn't one. Combining that with a COALESCE, we get
COALESCE(MAX(CASE WHEN commit_date <= to_date('2010-DEC-30', 'YYYY-MON-DD') THEN commit_date END), MAX(commit_date)).
Now we take the account id and commit date we have and join them with the original table to get all the other fields. Here's the whole query that I came up with:
SELECT *
FROM Account_Information
JOIN (SELECT account_id,
COALESCE(MAX(CASE WHEN commit_date <=
to_date('2010-DEC-30', 'YYYY-MON-DD')
THEN commit_date END),
MAX(commit_date)) AS commit_date
FROM Account_Information
WHERE account_id in (30000316, 30000350, 30000351)
GROUP BY account_id)
USING (account_id, commit_date);
Note that if you do use USING, you have to use * instead of acrt.*.