Get the Row with the Highest Value in MySQL

SQL select only rows with max value on a column

At first glance...

All you need is a GROUP BY clause with the MAX aggregate function:

SELECT id, MAX(rev)
FROM YourTable
GROUP BY id

It's never that simple, is it?

I just noticed you need the content column as well.

This is a very common question in SQL: find the whole data for the row with some max value in a column per some group identifier. I heard that a lot during my career. Actually, it was one the questions I answered in my current job's technical interview.

It is, actually, so common that Stack Overflow community has created a single tag just to deal with questions like that: greatest-n-per-group.

Basically, you have two approaches to solve that problem:

Joining with simple group-identifier, max-value-in-group Sub-query

In this approach, you first find the group-identifier, max-value-in-group (already solved above) in a sub-query. Then you join your table to the sub-query with equality on both group-identifier and max-value-in-group:

SELECT a.id, a.rev, a.contents
FROM YourTable a
INNER JOIN (
    SELECT id, MAX(rev) rev
    FROM YourTable
    GROUP BY id
) b ON a.id = b.id AND a.rev = b.rev

Left Joining with self, tweaking join conditions and filters

In this approach, you left join the table with itself. Equality goes in the group-identifier. Then, 2 smart moves:

1. The second join condition is having left side value less than right value
2. When you do step 1, the row(s) that actually have the max value will have NULL in the right side (it's a LEFT JOIN, remember?). Then, we filter the joined result, showing only the rows where the right side is NULL.

So you end up with:

SELECT a.*
FROM YourTable a
LEFT OUTER JOIN YourTable b
    ON a.id = b.id AND a.rev < b.rev
WHERE b.id IS NULL;

Conclusion

Both approaches bring the exact same result.

If you have two rows with max-value-in-group for group-identifier, both rows will be in the result in both approaches.

Both approaches are SQL ANSI compatible, thus, will work with your favorite RDBMS, regardless of its "flavor".

Both approaches are also performance friendly, however your mileage may vary (RDBMS, DB Structure, Indexes, etc.). So when you pick one approach over the other, benchmark. And make sure you pick the one which make most of sense to you.

MySQL - How to select rows with max value of a field

If you want to get ties, then you can do something like this:

select s.*
from scores s
where s.score = (select max(s2.score) from scores s2 where s2.level = s.level);

You could get one row per level by aggregating this:

select s.level, s.score, group_concat(s.user_id)
from scores s
where s.score = (select max(s2.score) from scores s2 where s2.level = s.level)
group by s.level, s.score;

This combines the users (if there is more than one) into a single field.

How to select a maximum value row in mysql table

Question 1 : What I made mistake here and why this MAX function is not return the relevant row information?

You need to read up on the group by clause.

MySQL is being a lot more permissive than it should, introducing confusion in the process. Basically, any column without an aggregate should be included in the group by clause. But MySQL syntactic sugar allows to "forget" columns. When you do, MySQL spits out an arbitrary value from the set that it's grouping by. In your case, the first row in the set is bob, so it returns that.

Question 2: Which one is good to use, to increase performance MAX function or ORDER BY clause?

Your first statement (using max() without a group by) is simply incorrect.

If you want one of the oldest users, order by age desc limit 1 is the correct way to proceed.

If you want all of the oldest users, you need a subselect:

SELECT p.* FROM people p WHERE p.age = (select max(subp.age) from people subp);

Get records with max value for each group of grouped SQL results

There's a super-simple way to do this in mysql:

select * 
from (select * from mytable order by `Group`, age desc, Person) x
group by `Group`

This works because in mysql you're allowed to not aggregate non-group-by columns, in which case mysql just returns the first row. The solution is to first order the data such that for each group the row you want is first, then group by the columns you want the value for.

You avoid complicated subqueries that try to find the max() etc, and also the problems of returning multiple rows when there are more than one with the same maximum value (as the other answers would do)

Note: This is a mysql-only solution. All other databases I know will throw an SQL syntax error with the message "non aggregated columns are not listed in the group by clause" or similar. Because this solution uses undocumented behavior, the more cautious may want to include a test to assert that it remains working should a future version of MySQL change this behavior.

Version 5.7 update:

Since version 5.7, the sql-mode setting includes ONLY_FULL_GROUP_BY by default, so to make this work you must not have this option (edit the option file for the server to remove this setting).

How can I SELECT a row with MAX(value) from a derived table where the values are all calculated sums?

Here's a solution that should work on any version of MySQL 5.x, using no ORDER BY, LIMIT, window functions, views, or CTEs.

SELECT a.stagename, a.total_salary
FROM (
      SELECT c.*, sum(p.dailySalary) as total_salary        
      from contender as c
      left join participant as p
      on (p.contender = c.idContender)
      group by c.idContender ) AS a
LEFT OUTER JOIN (
      SELECT c.*, sum(p.dailySalary) as total_salary        
      from contender as c
      left join participant as p
      on (p.contender = c.idContender)
      group by c.idContender ) AS b
  ON a.total_salary < b.total_salary
WHERE b.total_salary IS NULL;

Tested on MySQL 5.7.27.

Output:

+-------------+--------------+
| stagename   | total_salary |
+-------------+--------------+
| Bobbleheads |        11840 |
+-------------+--------------+

Select all rows where maximum value on a one column from two tables with union

As fix_id is unique in both tables, the answer with CASE statements (https://stackoverflow.com/a/65609931/53341) is likely the fastest (so, I've upvoted that)...

• Join once
• Compare rates, on each row
• Pick which table to read from, on each row

For large numbers of columns, however, it's unwieldy to type all the CASE statements. So, here is a shorter version, though it probably takes twice as long to run...

SELECT t1.*
  FROM table1 AS t1 INNER JOIN table2 AS t2 ON t1.fix_id = t2.fix_id
 WHERE t1.rate >= t2.rate

UNION ALL

SELECT t2.*
  FROM table1 AS t1 INNER JOIN table2 AS t2 ON t1.fix_id = t2.fix_id
 WHERE t1.rate <  t2.rate

MySQL - Is there a way I can get the other columns of a row which got the MAX value

You can use a subquery to list all the records with the maximum value:

 SELECT 'record_id', download_count as 'max_dl' FROM 'downloads' WHERE download_count = (SELECT MAX(download_count) FROM 'downloads')

how to get a Row with Max value of a column?

You can use a correlated subquery:

select t.*
from mytable t
where t.srno = (select max(srno) from mytable t1 where t1.p_id = t.p_id)

With an index on (p_id, srno), this should be an efficient solution.

Anoter common solution is to use row_number():

select pid, name, srno, rate
from (
    select t.*, row_number() over(partition by p_id order by srno desc) rn
    from mytable t
) t
where rn = 1

How can I SELECT rows with MAX(Column value), PARTITION by another column in MYSQL?

You are so close! All you need to do is select BOTH the home and its max date time, then join back to the topten table on BOTH fields:

SELECT tt.*
FROM topten tt
INNER JOIN
    (SELECT home, MAX(datetime) AS MaxDateTime
    FROM topten
    GROUP BY home) groupedtt 
ON tt.home = groupedtt.home 
AND tt.datetime = groupedtt.MaxDateTime

---

Related Topics