How to randomly select rows in SQL?
How to randomly select rows in SQL?
Question
I am using MSSQL Server 2005. In my db, I have a table "customerNames" which has two columns "Id" and "Name" and approx. 1,000 results.
I am creating a functionality where I have to pick 5 customers randomly every time. Can anyone tell me how to create a query which will get random 5 rows (Id, and Name) every time when query is executed?
Accepted Answer
SELECT TOP 5 Id, Name FROM customerNames
ORDER BY NEWID()
That said, everybody seems to come to this page for the more general answer to your question:
Selecting a random row in SQL
Select a random row with MySQL:
SELECT column FROM table
ORDER BY RAND()
LIMIT 1
Select a random row with PostgreSQL:
SELECT column FROM table
ORDER BY RANDOM()
LIMIT 1
Select a random row with Microsoft SQL Server:
SELECT TOP 1 column FROM table
ORDER BY NEWID()
Select a random row with IBM DB2
SELECT column, RAND() as IDX
FROM table
ORDER BY IDX FETCH FIRST 1 ROWS ONLY
Select a random record with Oracle:
SELECT column FROM
( SELECT column FROM table
ORDER BY dbms_random.value )
WHERE rownum = 1
Select a random row with sqlite:
SELECT column FROM table
ORDER BY RANDOM() LIMIT 1
Read more... Read less...
In case someone wants a PostgreSQL solution:
select id, name
from customer
order by random()
limit 5;
Maybe this site will be of assistance.
For those who don't want to click through:
SELECT TOP 1 column FROM table
ORDER BY NEWID()
There is a nice Microsoft SQL Server 2005 specific solution here. Deals with the problem where you are working with a large result set (not the question I know).
Selecting Rows Randomly from a Large Table http://msdn.microsoft.com/en-us/library/cc441928.aspx
If you have a table with millions of rows and care about the performance, this could be a better answer:
SELECT * FROM Table1
WHERE (ABS(CAST(
(BINARY_CHECKSUM
(keycol1, NEWID())) as int))
% 100) < 10