I am new in GQL and facing problem while fetching records from cloud data store. I want to show records according to time when it is saving in data store and whose status is less than 2(i.e 0 or 1). Users whose details are saved recently comes on top in listing and then others. While saving details I am storing their timestamp also. Here is my query to retrieve the details whose status is 0 (which is working fine) but I want to retrieve details whose status is both 0 or 1.
"NOTE: Status datatype is string in datastore."
According to the GQL rule we can't use OR operator in it. So, what will be the solution for it. Anyone knows?
SELECT * FROM Users WHERE __key__ HAS ANCESTOR KEY(UsersDetails, 9623495224) AND status = '0' ORDER BY sent_on desc
Instead of using OR you can do the following workaround:
SELECT * FROM Users WHERE __key__ HAS ANCESTOR KEY(UsersDetails, 9623495224) AND status >= 0 AND status <= 1 ORDER BY sent_on desc
Note that for this case you should convert the data to int. You can check the reference here
Related
Considering the following query:
SELECT TOP 1 * FROM c
WHERE c.Type = 'Case'
AND c.Entity.SomeField = #someValue
AND c.Entity.CreatedTimeUtc > #someTime
ORDER BY c.Entity.CreatedTimeUtc DESC
Until recently, when I ran this query, the number of documents processed by the query (RetrievedDocumentCount in the query metrics) was the number of documents that satisfies the first two condition, regardless the "CreatedTimeUtc" or the TOP 1.
Only when I added a composite index of (Type DESC, Entity.SomeField DESC, Entity.CreatedTimeUtc DESC) and added them to the ORDER BY clause, the retrieved documents count dropped to the number of documents that satisfies all 3 conditions (still not one document as expected, but better).
Then, starting a few days ago, we noticed in our dev environment that the composite index is no longer needed as retrieved documents count changed to only one document (= the number in the TOP, as expected), and the RU/s reduced significantly.
My question – is this a new improvement/fix in CosmosDB? I couldn’t find any announcement/documentation on this manner.
If so, is the roll-out completed or still in-progress? We have several production instances in different regions.
Thanks
There have not been any recent changes to our query engine that would explain why this query is suddenly less expensive.
The only thing that would explain this is fewer results match the filter than before and that our query engine was able to perform an optimization that it would not otherwise be able to have done with a larger set of results.
Thanks.
I am trying to select data based on a status which is a string. What I want is that status 'draft' comes first, so I tried this:
SELECT *
FROM c
ORDER BY c.status = "draft" ? 0:1
I get an error:
Unsupported ORDER BY clause. ORDER BY item expression could not be mapped to a document path
I checked Microsoft site and I see this:
The ORDER BY clause requires that the indexing policy include an index for the fields being sorted. The Azure Cosmos DB query runtime supports sorting against a property name and not against computed properties.
Which I guess makes what I want to do impossible with queries... How could I achieve this? Using a stored procedure?
Edit:
About stored procedure: actually, I am just thinking about this, that would mean, I need to retrieve all data before ordering, that would be bad as I take max 100 value from my database... IS there any way I can do it so I don t have to retrieve all data first? Thanks
Thanks!
ORDER BY item expression could not be mapped to a document path.
Basically, we are told we can only sort with properties of document, not derived values. c.status = "draft" ? 0:1 is derived value.
My idea:
Two parts of query sql: The first one select c.* from c where c.status ='draft',second one select c.* from c where c.status <> 'draft' order by c.status. Finally, combine them.
Or you could try to use stored procedure you mentioned in your question to process the data from the result of select * from c order by c.status. Put draft data in front of others by if-else condition.
I'm running this query on a sqlite db and it looks that its working fine.
SELECT batterij ,timestamp FROM temphobbykamer WHERE nodeid= 113 AND timestamp >= 1527889336634 AND timestamp <= 1530481336634 AND ROWID % 20 =0
But can i be sure that the query is handled in the correct order?
It must find all records from node113 between time A and B. From this selection found I only want to have every 20th record.
I can imagine if the query order difference, that if you query every 20th record between time A and B and select from this selection all the node113 records that the response will be different.
When no ORDER BY is specified, the order is undefined. However, typically sqlite will return in ROWID order since you haven't specified anything else. To make sure you get consistent results, you should specify ORDER BY ROWID
So I currently have a database that keeps tracks of projects, project updates, and the update dates. I have a form that with a subform that displays the project name and the most recent update made to said project. It was brought to my attention however, that the most recent update to a project does not display correctly. Ex: shows the update date of 4/6/2017 but the actual update text is from 3/16/2017.
Doing some spot research, I then learned that Access does not store records in any particular order, and that the Last function does not actually give you the last record.
I am currently scouring google to find a solution but to no avail as of yet and have turned here in hopes of a solution or idea. Thank you for any insight you can provide in advance!
Other details:
tblProjects has fields
ID
Owner
Category_ID
Project_Name
Description
Resolution_Date
Priority
Resolution_Category_ID
tblUpdates has these fields:
ID
Project_ID
Update_Date
Update
there is no built-in Last function that I am aware of in Access or VBA, where exactly are you seeing that used?
if your sub-form is bound directly to tblUpdates, then you ought to be able to just sort the sub-form in descending order based on either ID or Update_date.
if you have query joining the two tables, and are only trying to get a single row returned from tblUpdates, then this would do that, assuming the ID column in tblUpdates is an autonumber. if not, just replace ORDER BY ID with ORDER BY Update_Date Desc
SELECT a.*,
(SELECT TOP 1 Update FROM tblUpdates b WHERE a.ID = b.PROJECT_ID ORDER BY ID DESC ) AS last_update
FROM tblProjects AS a;
I am developing an Auction site in asp.net3.5 and sql server 2008R2, My Database has an Auction Table that has a calculated column "AuctionStatus" -
(case when [EndDateTime] < getdate() then '0' else '1' end)
that gives auction status Active or inactive based on End Date.
Now I want to call a stored procedure that sends email notifications to buyers and sellers as soon as AuctionStatus becomes '0'. For that i tried to create a after update trigger that could call the email notification sp, but i am not able to do so.
I am getting the following error message :-
Msg 2114, Level 16, State 1, Procedure trgAuctionEmailNotification,
Line 6 Column 'AuctionStatus' cannot be used in an IF UPDATE clause
because it is a computed column.
The trigger is:
CREATE TRIGGER trgAuctionEmailNotification ON SE_Auctions
AFTER UPDATE
AS
BEGIN
IF (UPDATE (AuctionStatus))
BEGIN
IF EXISTS (SELECT * FROM inserted WHERE currentbidderid > 0
AND AuctionStatus='0' )
BEGIN
DECLARE #ID int
SELECT #ID = AuctionID from inserted
EXEC spSelectSE_AuctionsByAuctionID #ID
END
END
END
You could just replace AuctionStatus with the corresponding expression :
IF EXISTS (SELECT * FROM inserted WHERE currentbidderid > 0 AND [EndDateTime] < getdate() )
But, the point is I don't see how your trigger will be "triggered" as [AuctionStatus] is never "updated". Its Value is just calculated whenever you need it.
You could go for a sql job that runs every x minutes and send a notification for each auction which ended during the last x minutes.
You need to add a real column containing a flag to indicate whether the notifications have been sent, and then implement a polling technique to scan the table for rows where the status is inactive and notifications haven't been sent.
The computed column doesn't really transition from one state to another, so it's not like an UPDATE has occurred. Even if SQL Server did implement this, it would be hideously expensive, since it would have to query the entire table for transitioning rows every 3ms. (or even more frequently if you're using datetime2 with a higher precision)
Whereas you can pick a suitable polling interval yourself. This could be an SQL agent job, or in some service code somewhere, whatever best fits the rest of your architecture.