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Mysql join latest record9/1/2023 ![]() I put this little example together for you Doug…copy/paste this and see what I mean:ĭECLARE table ( MachineName varchar(25) NOT NULL So, here’s another generalized query to help explain how that could be achieved. In addition, it was suggested to have a sample query for cases when you might want to join this to other tables. This is so that you can tell SQL which record from the main table you want to retrieve. ![]() The sub query is then joined to the same table on the entity AND the dates. It also occurred to me that perhaps I should give a quick explanation of what is going on with the sample query: The sub query is written to get the max date for each entity (in this case Machine). When creating an aggregate (such as MAX) you don’t want to group by the value you want to find the max of. ![]() It was grouping by the date desired in the MAX aggregate. After looking at the sub query I noticed the issue was with the GROUP BY portion of the query. Today someone reached out to ask why they couldn’t get this to work for them in their query. The following generalized query will allow you to do this. The record you want to see is the one with the latest information (determined by the date column).You don’t want to see multiple records for a given machine meaning, you want to only return one record per machine.The table has a date specifying the time of the record insert (or something like an inventory scan time).You have a table that can have multiple records for a given entity (such as a machine).I’ve been asked this a couple times over the past few months and again today so I thought I’d send it out in hopes that others will benefit from this. Note: there are multiple ways to do this but at the time I originally wrote this I only wrote about this one. I have left this as originally written but have updated formatting for my WordPress theme. #start select orders.* from orders, (select name,max(order_date) as order_date from orders group by name) max_sales where orders.name=max_sales.name and orders.order_date=max_sales.This was originally posted to my internal (to Microsoft) blog on as part of a series I called ‘SQL Tips’ for coworkers based on an email distribution list I sent out before the internal blog. #start select name,max(order_date) from orders group by name #endĪs we now know the most recent date for each group of records, we can join this data with our original table so that we can get the most recent record for each group of records. In the first step, we are going to use GROUP BY to get the most recent date for each group. In our example, let’s say that you have a table orders (name, order_date, amount) that contains sales data for a number of products at the same time.ġ.Create Table #start create table orders(name varchar(255),order_date date, amount int) #endĢ.Insert Data #start insert into orders(name,order_date, amount) values('Aa','',2500), ('Bb','',3500), ('Cb','',12500), ('Aa','',4500), ('Bb','',6500), ('Cc','',10500), ('Aa','',1500), ('Bb','',2500), ('Cc','',18500) #endįor example, let’s say that you want to get the last record for each group, that is, for each product. The following steps will show you how to get the last record in each group in MySQL. It can also be used to select the last row for each group in PostgreSQL, SQL Server, and Oracle databases. The following SQL query will retrieve the last record in each group in MySQL because there is no built-in function to do this in MySQL. In some cases it may be necessary to select the most recent record or get the most recent record for a particular date, user, ID or any other group. How To Get Last Record In Each Group In MySQL
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