SQL query for select distinct with most recent timestamp first

Posted by Josh on Stack Overflow See other posts from Stack Overflow or by Josh
Published on 2012-03-26T05:18:52Z Indexed on 2012/03/26 5:29 UTC
Read the original article Hit count: 326

Filed under:

sql

|

query

I have a mysql table with three columns: username, location, timestamp. This is basically a log of user activity of what location they are in and the time that they were there.

What I want to do is select a distinct username+location where only the most recent item (by timestamp) is provided.

So say the table consists of:

tom roomone 2011-3-25 10:45:00
tom roomtwo 2011-3-25 09:00:00
tom roomtwo 2011-3-25 08:30:00
pam roomone 3011-3-25 07:20:23

I would want only these to be selected:

tom roomone 2011-3-25 10:45:00
tom roomtwo 2011-3-25 09:00:00

© Stack Overflow or respective owner

Related posts about sql

SQL SERVER – Concat Strings in SQL Server using T-SQL – SQL in Sixty Seconds #035 – Video

as seen on SQL Authority - Search for 'SQL Authority'
Concatenating string is one of the most common tasks in SQL Server and every developer has to come across it. We have to concat the string when we have to see the display full name of the person by first name and last name. In this video we will see various methods to concatenate the strings. SQL… >>> More
SQL SERVER – Concat Function in SQL Server – SQL Concatenation

as seen on SQL Authority - Search for 'SQL Authority'
Earlier this week, I was delivering Advanced BI training on the subject of “SQL Server 2008 R2″. I had great time delivering the session. During the session, we talked about SQL Server 2010 Denali. Suddenly one of the attendees suggested his displeasure for the product. He said, even though… >>> More
Error with SQL Server Setup 2012 on Windows 2012

as seen on Server Fault - Search for 'Server Fault'
I am trying to install SQL Server on Windows 2012. I was able to finally get the wizard up and running after making some changes on the server, but now it fails no matter what I do with the following error: TITLE: SQL Server Setup failure. SQL Server Setup has encountered the following error: … >>> More
How can I detect which version of SQL (eg SQL 2008 or SQL Azure)

as seen on Stack Overflow - Search for 'Stack Overflow'
I need to detect which version of SQL I am dealing with to perorm various tasks, I need specifically detect if I am on SQL 2008 or SQL Azure. How can I do this with detection code written in SQL? >>> More
Nested SQL Select statement fails on SQL Server 2000, ok on SQL Server 2005

as seen on Stack Overflow - Search for 'Stack Overflow'
Here is the query: INSERT INTO @TempTable SELECT UserID, Name, Address1 = (SELECT TOP 1 [Address] FROM (SELECT TOP 1 [Address] FROM [UserAddress] ua INNER JOIN UserAddressOrder uo ON ua.UserID = uo.UserID WHERE ua.UserID = u.UserID ORDER BY uo.AddressOrder ASC) q ORDER BY AddressOrder… >>> More

Related posts about query

sort mysql query by filtered query

as seen on Stack Overflow - Search for 'Stack Overflow'
I have two mysql queries: $sql = "SELECT * FROM content WHERE threadName LIKE '%$filter%' ORDER BY lastUpdated desc"; and $sql = "SELECT * FROM content ORDER BY lastUpdated desc"; The end result is to have all rows returned from a particular table 'content' but have those that match the variable… >>> More
How to use PHPunit's Database Test Case Methods of Query to compare with doctrine query

as seen on Stack Overflow - Search for 'Stack Overflow'
How to use PHPunit's Database Test Case Methods of Query to compare with doctrine query i m using phpunit with doctrine framework .. i want to test my doctrine query with phpunit query with using phpunit framework methods.. any buddy with Doctrine Query and PhpUnit Query plz Contact... //Bhavin… >>> More
Converting sql query to EF query - nested query in from

as seen on Stack Overflow - Search for 'Stack Overflow'
Hey guys Just wondering how the following sql query would look in linq for Entity Framework... SELECT KPI.* FROM KeyPerformanceIndicator KPI INNER JOIN ( SELECT SPP.SportProgramPlanId FROM SportProgramPlan PSPP INNER JOIN SportProgramPlan ASPP … >>> More
Sql Query - Limiting query results

as seen on Stack Overflow - Search for 'Stack Overflow'
I am quite certain we cannot use the LIMIT clause for what I want to do - so wanted to find if there are any other ways we can accomplish this. I have a table which captures which user visited which store. Every time a user visits a store, a row is inserted into this table. Some of the fields are shopping_id… >>> More
hql equivalent query to this sql query

as seen on Stack Overflow - Search for 'Stack Overflow'
Select top 1 from <tablename> what is hql query for the above ? >>> More