Tuesday, August 11, 2009
Get percentage of records from a table
2:27 PM | 
Posted by
Sheen
Have you ever come across a situation where you need to get top 25%
records from a table. Here is the SQL that returns first 25% of records from a table.
SELECT TOP 25 PERCENT *
FROM dbo.yourtable
This will return what you want, the 25% of records from the table. What if you want the second 25% of records.
SELECT TOP 50 PERCENT *
FROM ( SELECT TOP 50 PERCENT *
FROM dbo.yourtable) results ORDER BY 1 DESC
On the above query by descending the records by first column, assuming that it is the primerykey or the records we need to filter by, you will get the top 25% which is the second 25% of the records.
Think how to get the third and the last 25% records leisurely.
Labels:
Subscribe to:
Post Comments (Atom)
My Achievements
_504.gif){kind=small}
_513.gif){kind=small}
.gif)
Member of
Important Blogs
-
-
Git Workflow For Enterprise development6 years ago
-
-
Watch Live Cricket Online Free14 years ago
-
-
-
4 comments:
3rd 25%
SELECT TOP 25 PERCENT *
FROM ( SELECT TOP 75 PERCENT *
FROM dbo.yourtable) results ORDER BY 1 DESC
4th 25%
SELECT TOP 25 PERCENT *
FROM dbo.yourtable
ORDER BY 1 DESC
Hope i am right... Keep updating the blog pal :)
Tharaka small change needs to be done in yor query. As in your query it will return 25% from the 75% of the sub query. In the sub query you have to take 50% of whole table in descending order which will give you 2nd 50% of the records and then select 50% from that sub query.
3rd 25%
SELECT TOP 50 PERCENT *
FROM ( SELECT TOP 50 PERCENT *
FROM dbo.yourtable ORDER BY 1 DESC) results ORDER BY 1
4th 25%
The query you wrote is correct but it will return a descending order result.
SELECT * FROM (SELECT TOP 25 PERCENT *
FROM Customer ORDER BY 1 DESC) results ORDER BY 1
Thnx mate
My mistake... Agree with you machan :)
Post a Comment