i wanna compare time and show records that are greater than the spcified time. For example in my database I have a field "TimeDate" where I store date and time together. Now i want to show records that are only greater than lets say this time "19/04/2012 2:34:27 PM". Is there anyway I can achieve this.
I have started with this code.
Select * from Table where TimeDate > '19/04/2012 2:34:27 PM'.
First of all the datatype is datetime in sql,
your sample code is right.
I am sure that sql is intelligent enough, for your current query.
Related
i want to get all entries from a SQLite table, which have the timestamp from the same month.
For example, the user can type in "July" and then i want to get all entries made in the 7. month.
The current "time"-column is a simple string and in the Format (DD.MM.YYYY HH:MM:SS)
Is there a way to do this with SQLite or will i need to use code in my program?
Assuming that your time strings have a fixed length, you could use a query like this:
SELECT * FROM MyTable WHERE time LIKE '__.07%';
However, you should always stored dates in one of the supported date/time formats so that you are able to use the built-int date/time functions.
My database table have a Timestamp column named as inTime and i am using LINQ for insert, update data in SQL server. Now i want to add the timestamp value in my database but i don't know how to insert?
spaBL.attendance obj = new spaBL.attendance();
obj.FK_employeeId = 1;
obj.inTime =[what to write here??]
inTime is of timestamp type.
Timestamp as in SQL Server Timestamp data type?
;) If I got a cent every time someone did not read the documentation and thought that is a TIME STAMP I would be more rich than bill gates.
Timestamp data time has NO TIME INFORMATION IN IT. It is a running version number, legacy to Sybase SQL Server where SQL Server from Microsoft originated and a totally borked design.
So, no, you CAN NOT SET THAT FIELD, sorry, and it has no usable value except to see whether it changed (then the row was updated).
The documentation is explicitly clear on that, even if some people think reading is maybe a lost art:
http://msdn.microsoft.com/en-us/library/ms182776(v=sql.90).aspx
Is a data type that exposes automatically generated, unique binary
numbers within a database. timestamp is generally used as a mechanism
for version-stamping table rows.
There is no way for you to set it. CHange your LINQ setup to not update this column.
Timestamp values are auto generated by the server on inserts. You should insert rows to the table without supplying a value for the timestamp column. Sql server will then generate the value for the column.
Note the columns of type timestamp does NOT contain values that can be parsed as a DateTime. The idea behind timestamp columns is that they can be used to check if a row has been updated between fetching the row and trying to update the row with new values.
You do not provide values for columns with a Timestamp (Rowversion) data type. SQL Server will provide a value for you automatically (and it won't be a datetime value). Therefore you do not need to be concerned with having Linq To SQL insert a Timestamp value for you. In fact, you cannot do it. SQL Server will do it for you. You can however, retrieve the value of a Timestamp column. I believe the corresponding C# type will be System.Data.Linq.Binary.
How to add Timestamp value in SQL database by using LINQ
hope it helps
You cannot update a timestamp. See here. And indeed, as TomTom indicated, it doesn't contain actual time information.
I've got a query where I'm trying to get the hours in duration (eg 6.5 hours) between two different times.
In my database, time and date are held in different fields so I can efficiently query on just a startDate, or endDate as I never query specifically on time.
My query looks like this
SELECT COUNT(*), IFNULL(SUM(TIMEDIFF(endTime,startTime)),0) FROM events WHERE user=18
Sometimes an event will go overnight, so the difference between times needs to take into account the differences between the dates as well.
I've been trying
SELECT COUNT(*), IFNULL(SUM(TIMEDIFF(CONCAT(endDate,' ',endTime),CONCAT(startDate,' ',startTime))),0) FROM events WHERE user=18
Unfortunately I only get errors when I do this, and I can't seem to combine the two fields into a single timestamp.
Pretty sure your problem is that your concatenated values are being sent to TIMEDIFF() as strings rather than DATETIMEs. Try calling the DATETIME function on them:
SELECT COUNT(*), IFNULL(SUM(TIMEDIFF(DATETIME(CONCAT(endDate,' ',endTime)),DATETIME(CONCAT(startDate,' ',startTime)))),0) FROM events WHERE user=18
I don't have a MySQL DB in front of my to test that, but I think that or some similar form of it is what you are looking for. There's an example of it in the MySQL docs involving MICROSECOND:
http://dev.mysql.com/doc/refman/5.0/en/datetime.html
Edit: Hmm... looks like TIMEDIFF is supposed to work with strings. Worth trying anyway.
TIMEDIFF(endDate,startDate) + TIMEDIFF(endTime,startTime)
I am trying to correct the sort order of my ASP.NET drop down list.
The problem I have is that I need to select a distinct Serial number and have these numbers organised by DateTime Desc.
However I cannot ORDER BY DateTime if using DISTINCT without selecting the DateTime field in my query.
However if I select DateTime this selects every data value associated with a single Serial number and results in duplications.
The purpose of my page is to display data for ALL Serials, or data associated to one serial. When a new cycle begins (because it is a new production run) the Serial reverts to 1. So I cannot simply organise by serial number either.
When I use the following SQL statement the list box is in the order I require but after a period of time (usually a few hours) the order changes and appears to have no organised structure.
alt text http://img7.imageshack.us/i/captureky.jpg/
I'm fairly new to ASP.NET / SQL, does anyone know of a solution to my problem.
If you have multiple date times for each serial number, then which do you want to use for ordering? If the most recent, try this:
SELECT SerialNumber,
MAX(DateTimeField)
FROM Table
GROUP BY SerialNumber
ORDER BY 2 DESC
I don´t know if everybody agrees with that, but when I see a DISTINCT in a query the first thought that goes trough my mind is "This is wrong". Generally, DISTINCT is not necessary and it´s used when the person writing the query doesnt know very well what he is doing and this might be the case since you said you are new with Sql.
Without complete knowledge of your model is difficult to assist you a hundred percente, but I would say that you should use a GROUP BY clause instead of DISTINCT, then you can order it correctly.
My table contains Birthdate field which has datatype as datetime.
I want to get all records having birthday today.
How can I get it?
Try this query:
SELECT * FROM mytable
WHERE strftime('%m-%d', 'now') = strftime('%m-%d', birthday)
Having a special datetime type has always seemed like unnecessary overhead to me, integers are fast, flexible, and use less space.
For general datetime values use Unix Epoch timestamps. Easy to work with, extremely flexible, as well as timezone (and even calender!) agnostic. (I recently wrote an article on using them, which I really have to plug...)
That said, if you're only interested in dates in the Gregorian calendar you may want to use a large integer in the following format: YYYYMMDD, eg 19761203. For you particular usage you could even create a four digit integer like MMDD, say 1703 — that's got to result in fast selects!
SQLite has very poor support for storing dates. You can use the method suggested by Nick D above but bear in mind that this query will result in full table scan since dates are not indexed correctly in SQLite (actually SQLite does not support dates as a built-in type at all).
If you really want to do a fast query then you'll have to add a separate (integral) column for storing the birth day (1-31) and attach an index for it in the database.
If you only want to compare dates then you can add a single (INTEGER) column that will store the date UTC value (but this trick won't allow you to search for individual date components easily).
Good Luck