Get most recent row for given ID - mysql

Question

In the table below, how do I get just the most recent row with id=1 based on the signin column, and not all 3 rows?
+----+---------------------+---------+
| id | signin | signout |
+----+---------------------+---------+
| 1 | 2011-12-12 09:27:24 | NULL |
| 1 | 2011-12-13 09:27:31 | NULL |
| 1 | 2011-12-14 09:27:34 | NULL |
| 2 | 2011-12-14 09:28:21 | NULL |
+----+---------------------+---------+

Answer 1

Use the aggregate MAX(signin) grouped by id. This will list the most recent signin for each id.
SELECT
id,
MAX(signin) AS most_recent_signin
FROM tbl
GROUP BY id
To get the whole single record, perform an INNER JOIN against a subquery which returns only the MAX(signin) per id.
SELECT
tbl.id,
signin,
signout
FROM tbl
INNER JOIN (
SELECT id, MAX(signin) AS maxsign FROM tbl GROUP BY id
) ms ON tbl.id = ms.id AND signin = maxsign
WHERE tbl.id=1

Answer 2

SELECT *
FROM tbl
WHERE id = 1
ORDER BY signin DESC
LIMIT 1;
The obvious index would be on (id), or a multicolumn index on (id, signin DESC).
Conveniently for the case, MySQL sorts NULL values last in descending order. That's what you typically want if there can be NULL values: the row with the latest not-null signin.
To get NULL values first:
ORDER BY signin IS NOT NULL, signin DESC
You may want to append more expressions to ORDER BY to get a deterministic pick from (potentially) multiple rows with NULL.
The same applies without NULL if signin is not defined UNIQUE.
Related:
mysql order by, null first, and DESC after
The SQL standard does not explicitly define a default sort order for NULL values. The behavior varies quite a bit across different RDBMS. See:
https://docs.mendix.com/refguide/null-ordering-behavior
But there are the NULLS FIRST / NULLS LAST clauses defined in the SQL standard and supported by most major RDBMS, but not by MySQL. See:
SQL how to make null values come last when sorting ascending
Sort by column ASC, but NULL values first?

Answer 3

Building on #xQbert's answer's, you can avoid the subquery AND make it generic enough to filter by any ID
SELECT id, signin, signout
FROM dTable
INNER JOIN(
SELECT id, MAX(signin) AS signin
FROM dTable
GROUP BY id
) AS t1 USING(id, signin)

Answer 4

Select [insert your fields here]
from tablename
where signin = (select max(signin) from tablename where ID = 1)

Answer 5

SELECT * FROM (SELECT * FROM tb1 ORDER BY signin DESC) GROUP BY id;

Answer 6

I had a similar problem. I needed to get the last version of page content translation, in other words - to get that specific record which has highest number in version column. So I select all records ordered by version and then take the first row from result (by using LIMIT clause).
SELECT *
FROM `page_contents_translations`
ORDER BY version DESC
LIMIT 1

Answer 7

Simple Way To Achieve
I know it's an old question
You can also do something like
SELECT * FROM Table WHERE id=1 ORDER BY signin DESC
In above, query the first record will be the most recent record.
For only one record you can use something like
SELECT top(1) * FROM Table WHERE id=1 ORDER BY signin DESC
Above query will only return one latest record.
Cheers!