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How to get top rows for groups in MySQL?
NOTE:This question builds on a previous one- Get records with max value for each group of grouped SQL results- for getting a single top row from each group, and which received a great MySQL-specific answer from @Bohemian: select * from (select * from mytable order by `Group`, Age desc, Person) x group by `Group`
How to get groupnumber of two groups in MySQL?
This works with two groups, if you have more than two groups, then you would need to specify the groupnumber and add queries for each group: ( select * from mytable where `group` = 1 order by age desc LIMIT 2 ) UNION ALL ( select * from mytable where `group` = 2 order by age desc LIMIT 2 )
Can a group by query be used alone?
Any help will be appreciated. GROUP BY cannot be used alone because it only returns 1 row per group ( category ). You can use a sub query with flag = 1 and INNER JOIN: DISTINCT aren’t needed if, for each category, only 1 row can have flag = 1.
How to select the latest record in each group?
In this situation, we can choose to run an SQL statement that will return the latest record in each group. For the purpose of this post, assume that we have deployed multiple Raspberry Pis to capture temperature and humidity in different locations.
How to return the last row of each group by in MySQL?
Returning the last row of each GROUP BY in MySQL with WHERE clause: SELECT * FROM foo WHERE id IN ( SELECT Max (id) FROM foo WHERE value=’XYZ’ GROUP BY u_id ) LIMIT 0,30. Share. edited Jul 14 ’17 at 4:33. josemmo.
How to get Max age for each group in MySQL?
SELECT t1.* FROM yourTable t1 INNER JOIN ( SELECT `Group`, MAX (Age) AS max_age FROM yourTable GROUP BY `Group` ) t2 ON t1.`Group` = t2.`Group` AND t1.Age = t2.max_age; However it doesn’t work in PostgreSQL and maybe some other platforms.
How to get the latest date from grouped MySQL data?
If you’re looking for all models matching the max date of the entire table… For those who want to display details from every record matching the latest date within each model group (not summary data, as asked for in the OP): MySQL 8.0 and newer supports the OVER clause, producing the same results a bit faster for larger data sets.