sql query to get earliest date

While using TOP or a sub-query both work, I would break the problem into steps:

Find target record

SELECT MIN( date ) AS date, id
FROM myTable
WHERE id = 2
GROUP BY id

Join to get other fields

SELECT mt.id, mt.name, mt.score, mt.date
FROM myTable mt
INNER JOIN
( 
   SELECT MIN( date ) AS date, id
   FROM myTable
   WHERE id = 2
   GROUP BY id
) x ON x.date = mt.date AND x.id = mt.id

While this solution, using derived tables, is longer, it is:

  • Easier to test
  • Self documenting
  • Extendable

It is easier to test as parts of the query can be run standalone.

It is self documenting as the query directly reflects the requirement ie the derived table lists the row where id = 2 with the earliest date.

It is extendable as if another condition is required, this can be easily added to the derived table.


If you just want the date:

SELECT MIN(date) as EarliestDate
FROM YourTable
WHERE id = 2

If you want all of the information:

SELECT TOP 1 id, name, score, date
FROM YourTable
WHERE id = 2
ORDER BY Date

Prevent loops when you can. Loops often lead to cursors, and cursors are almost never necessary and very often really inefficient.


SELECT TOP 1 ID, Name, Score, [Date]
FROM myTable
WHERE ID = 2
Order BY [Date]

Try

select * from dataset
where id = 2
order by date limit 1

Been a while since I did sql, so this might need some tweaking.

Tags:

Sql

Sql Server