I am wondering if it's possible to use a view to get the top 5 lines from a table.
I am finding that Crystal reports doesn't seem to have anything built in to do this, or I'd do it there.
When I query the view Select * from qryTranHistory, it returns the first 5 items, but if I try to select a specific type Select * from qryTranHistory Where tID = 45 it returns nothing, since there are no tID=45 in the top 5 normally.
Is it possible to do this?
Can it be accomplished in a sub report in Crystal Reports?
It is easy to limit a report to the top 5 records. In the menu, just choose
Report --> Selection Formulas... --> Group
In the formula, enter "RecordNumber <= 5" and you are done.
You don't need to have a group field nor summary field to do the group filter. You don't need a sort order, but using top N records without a sort order doesn't usually make much sense. It might not be efficient as OMG Ponies suggested, but for small number of records it is OK.
You can reference a sproc from Crystal Reports. In the sproc, use a conditional on the parameter.
ALTER PROCEDURE dbo.Get_TOP5
(
#tID INT = NULL
)
AS
IF #tID IS NULL
BEGIN
SELECT TOP 5
FIELD1,
FIELD2
FROM qryTranHistory
END
ELSE
BEGIN
SELECT
FIELD1,
FIELD2
FROM qryTranHistory
WHERE tID =#tID
END
A simple setting can limit the records to top 5!! Here it is, if you're using .Net 1.1 (similar arrangement of options in higher frameworks too!).
Right click on the report layout > Reports > Top N/Sort Group Expert > Choose Top N in the Dropdown that asks for the type of filtering/ sorting you wish to do > Set the Value of top N (5 in your case) > Uncheck the option that includes other records.
Your report will be filtered for only the top 5 records from the Dataset.
There's another way how it could be done and that is through the Record selection formula where you limit the No. of records, as suggested by John Price in this thread.
Cheers!
Can you put the TOP in your SELECT statement instead of in the view?
SELECT TOP 5
col1,
col2,
...
FROM
qryTranHistory
WHERE
tid = 45
If your table has more then 5 rows I hope this query:
SELECT * FROM qryTranHistory
Returns more then 5 rows because you never mentioned TOP 5.
Your question doesn't make a lot of sense as I am not sure waht you are after.
You mentioned if you ran your query with WHERE tID=45, it returns nothing, what exactly do you want it to return ?
Read up on TOP in BOL:
SELECT TOP 10 Recs FROM Records WHERE...
By the way you do not want to do this in the report / a form interface, you want to do this in your db layer.
You can do Top N processing in Crystal Reports, but it's a little obscure - you have to use the group sort expert (and in order to use that, you need to have groups and summary fields inserted into the groups.)
Doing the Top N processing in the query should be more efficient, where possible.
If you have a small recordset, you can create a running total that counts the change of rows (field1), then in Section Expert in Details, tell it to supress RTotal0 (your running total variable) to > 5
Related
I have a 450GB database... with millions of records.
Here is an example query:
SELECT TOP 1 * FROM c WHERE c.type='water';
To speed up our queries, I thought about just taking the first one but we have noticed that the query still takes quite a while, despite the very first record in the database matching our constraints.
So, my question is, how does the SELECT TOP 1 really work? Does it:
A) Select ALL records and then return just the first (top) one where
type='water'
B) Return the first record which is encountered where type='water'
Try this line, noting the offset limit:
SELECT * FROM c WHERE c.type='water' OFFSET 0 LIMIT 1
For more information about the offset limit:
https://learn.microsoft.com/en-us/azure/cosmos-db/sql-query-offset-limit
Assuming you aren't sorting your results (which you query isn't) then TOP 1 will return the first result as soon as it finds one. This should then end the query.
Cosmos db Explorer doesn't work with the TOP Command, It's an existing issue. It works fine in SDK Call.
Check some Top command usage below
https://learn.microsoft.com/en-us/azure/cosmos-db/sql-query-subquery
I have a matrix in ssrs2008 like below:
GroupName Zone CompletedVolume
Cancer 1 7
Tunnel 1 10
Surgery 1 64
ComplatedVolume value is coming by a specific expression <<expr>>, which is equal to: [Max(CVolume)]
This matrix is filled by a stored procedure that I am not supposed to change if possible. What I need to do is that not to show the data whose CompletedVolume is <= 50. I tried to go to tablix properties and add a filter like [Max(Q9Volume)] >= 50, but when I try to run the report it says that aggregate functions cannot be used in dataset filters or data region filters. How can I fix this as easy as possible?
Note that adding a where clause in sql query would not solve this issue since there are many other tables use the same SP and they need the data where CompletedVolume <= 50. Any help would be appreciated.
EDIT: I am trying to have the max(Q9Volume) value on SP, but something happening I have never seen before. The query is like:
Select r.* from (select * from results1 union select * from results2) r
left outer join procedures p on r.pid = p.id
The interesting this is there are some columns I see that does not included by neither results1/results2 nor procedures tables when I run the query. For example, there is no column like Q9Volume in the tables (result1, result2 and procedures), however when I run the query I see the columns on the output! How is that possible?
You can set the Row hidden property to True when [Max(CVolume)] is less or equal than 50.
Select the row and go to Row Visibility
Select Show or Hide based on an expression option and use this expression:
=IIF(
Max(Fields!Q9Volume.Value)<=50,
True,False
)
It will show something like this:
Note maximum value for Cancer and Tunnel are 7 and 10 respectively, so
they will be hidden if you apply the above expression.
Let me know if this helps.
I have this query in Access:
SELECT TOP 10 title,
ConcatRelated("DOCTEXT","DocumFrag", "title='" & title & "'" ) AS result
FROM DocumFrag
GROUP BY title;
DocumFrag contains about 9000 records, ConcatRelated is VBA code found here: http://allenbrowne.com/func-concat.html
When I run this query for only TOP 10 and it completes, it continually lags to the point of 20 second response time (clicking, typing, etc).
Is there a way I can improve this to be more stable? I'm doing TOP 10 as an example to test if it lags; in the end I'd need to select all.
My goal of this query is the same as Concatenating record values in database (MS Access) or in server side code (ASP.NET) (except in Access, not ASP.NET)
Or is there a way I can accomplish this using a query, instead of VBA?
My best guess is that ConcatRelated evaluates for every 'title' in 'DocumFrag'. Select the top 10 in an inner query before you apply the function:
SELECT q.title, ConcatRelated("DOCTEXT","DocumFrag", "title='" & q.title & "'" ) AS result
FROM
(SELECT TOP 10 title FROM DocumFrag) AS q
GROUP BY q.title;
yes, 1st make sure your data table has a clustered index (this determines the order the data is stored on disk), otherwise you have a heap and the sql engine needs to query the entire table as the data can be anywhere in the table. 2nd put a covering index on the querying parameters and the data you want to return. 3rd you are trying to group text? It would be better to Find the top 10 items and then conconate the text associate with them rather than conconate every group item as your code is doing and then select the top 10.
Is there a way to include a blank row at the top of a sql query, eg if it is meant for a dropdown list? (MS Sql Server 2005 or 2008)
Select *
FROM datStatus
ORDER BY statusName
Where I want something like
-1 (please choose one)
1 Beginning
2 Middle
3 Ending
4 Canceled
From a table that is ordinarily just the above, but without the top row?
I feel it's nicer to do it outside SQL, but if you insist...
SELECT -1, '(please choose one)'
UNION
SELECT * FROM datStatus
ORDER BY statusName
I have found that it is better to do this in the presentation layer of your application, as you might have different requirements based on the context. In general I try to keep my data service layer free of these sorts of implementation specific rules. So in your case I would usually just add a new item by index in the first position of the list, after i had loaded it with data from my service layer.
Enjoy!
How about unioning the first row together with the rest of the query?
Select -1,'(please choose one)'
union all
select * FROM datStatus ORDER BY statusName
I am attempting to pull ALOT of data from a fox pro database, work with it and insert it into a mysql db. It is too much to do all at once so want to do it in batches of say 10 000 records. What is the equivalent to LIMIT 5, 10 in Fox Pro SQL, would like a select statement like
select name, address from people limit 5, 10;
ie only get 10 results back, starting at the 5th. Have looked around online and they only make mention of top which is obviously not of much use.
Take a look at the RecNo() function.
FoxPro does not have direct support for a LIMIT clause. It does have "TOP nn" but that only provides the "top-most records" within a given percentage, and even that has a limitation of 32k records returned (maximum).
You might be better off dumping the data as a CSV, or if that isn't practical (due to size issues), writing a small FoxPro script that auto-generates a series of BEGIN-INSERT(x10000)-COMMIT statements that dump to a series of text files. Of course, you would need a FoxPro development environment for this, so this may not apply to your situation...
Visual FoxPro does not support LIMIT directly.
I used the following query to get over the limitation:
SELECT TOP 100 * from PEOPLE WHERE RECNO() > 1000 ORDER BY ID;
where 100 is the limit and 1000 is the offset.
It is very easy to get around LIMIT clause using TOP clause ; if you want to extract from record _start to record _finish from a file named _test, you can do :
[VFP]
** assuming _start <= _finish, if not you get a top clause error
*
_finish = MIN(RECCOUNT('_test'),_finish)
*
SELECT * FROM (SELECT TOP (_finish - _start + 1) * FROM (SELECT TOP _finish *, RECNO() AS _tempo FROM _test ORDER BY _tempo) xx ORDER BY _tempo DESC) yy ORDER BY _tempo
**
[/VFP]
I had to convert a Foxpro database to Mysql a few years ago. What I did to solve this was add an auto-incrementing id column to the Foxpro table and use that as the row reference.
So then you could do something like.
select name, address from people where id >= 5 and id <= 10;
The Foxpro sql documentation does not show anything similar to limit.
Here, adapt this to your tables. Took me like 2 mins, i do this waaaay too often.
N1 - group by whatever, and make sure you got a max(id), you can use recno() to make one, sorted correctly
N2 - Joins N1 where the ID = Max Id of N1, display the field you want from N2
Then if you want to join to other tables, put that all in brackets and give it an alias and include it in a join.
Select N1.reference, N1.OrderNoteCount, N2.notes_desc LastNote
FROM
(select reference, count(reference) OrderNoteCount, Max(notes_key) MaxNoteId
from custnote
where reference != ''
Group by reference
) N1
JOIN
(
select reference, count(reference) OrderNoteCount, notes_key, notes_desc
from custnote
where reference != ''
Group by reference, notes_key, notes_desc
) N2 ON N1.MaxNoteId = N2.notes_key
To expand on Eyvind's answer I would create a program to uses the RecNo() function to pull records within a given range, say 10,000 records.
You could then programmatically cycle through the large table in chucks of 10,000 records at a time and preform your data load into you MySQL database.
By using the RecNO() function you can be certain not to insert rows more than once, and be able to restart at a know point in the data load process. That by it's self can be very handy in the event you need to stop and restart the load process.
Depending on the number of the returned rows and if you are using .NET Framework you can offset/limit the gotten DataTable on the following way:
dataTable = dataTable.AsEnumerable().Skip(offset).Take(limit).CopyToDataTable();
Remember to add the Assembly System.Data.DataSetExtensions.