I'm interested in learning some (ideally) database agnostic ways of selecting the nth row from a database table. It would also be interesting to see how this can be achieved using the native functionality of the following databases:
I am currently doing something like the following in SQL Server 2005, but I'd be interested in seeing other's more agnostic approaches:
WITH Ordered AS ( SELECT ROW_NUMBER() OVER (ORDER BY OrderID) AS RowNumber, OrderID, OrderDate FROM Orders) SELECT * FROM Ordered WHERE RowNumber = 1000000
Credit for the above SQL: Firoz Ansari's Weblog
Update: See Troels Arvin's answer regarding the SQL standard. Troels, have you got any links we can cite?
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~ Asked on 2008-08-19 17:13:11
There are ways of doing this in optional parts of the standard, but a lot of databases support their own way of doing it.
A really good site that talks about this and other things is http://troels.arvin.dk/db/rdbms/#select-limit.
Basically, PostgreSQL and MySQL supports the non-standard:
SELECT... LIMIT y OFFSET x
Oracle, DB2 and MSSQL supports the standard windowing functions:
SELECT * FROM ( SELECT ROW_NUMBER() OVER (ORDER BY key ASC) AS rownumber, columns FROM tablename ) AS foo WHERE rownumber <= n
(which I just copied from the site linked above since I never use those DBs)
Update: As of PostgreSQL 8.4 the standard windowing functions are supported, so expect the second example to work for PostgreSQL as well.
Update: SQLite added window functions support in version 3.25.0 on 2018-09-15 so both forms also work in SQLite.
~ Answered on 2008-08-19 19:22:15
SELECT * FROM mytable ORDER BY somefield LIMIT 1 OFFSET 20;
This example selects the 21st row.
OFFSET 20 is telling Postgres to skip the first 20 records. If you don't specify an
ORDER BY clause, there's no guarantee which record you will get back, which is rarely useful.
~ Answered on 2008-08-19 17:31:23
I'm not sure about any of the rest, but I know SQLite and MySQL don't have any "default" row ordering. In those two dialects, at least, the following snippet grabs the 15th entry from the_table, sorting by the date/time it was added:
SELECT * FROM the_table ORDER BY added DESC LIMIT 1,15
(of course, you'd need to have an added DATETIME field, and set it to the date/time that entry was added...)
~ Answered on 2008-08-19 17:20:33
SQL 2005 and above has this feature built-in. Use the ROW_NUMBER() function. It is excellent for web-pages with a << Prev and Next >> style browsing:
SELECT * FROM ( SELECT ROW_NUMBER () OVER (ORDER BY MyColumnToOrderBy) AS RowNum, * FROM Table_1 ) sub WHERE RowNum = 23
~ Answered on 2009-07-09 15:00:46
I suspect this is wildly inefficient but is quite a simple approach, which worked on a small dataset that I tried it on.
select top 1 field from table where field in (select top 5 field from table order by field asc) order by field desc
This would get the 5th item, change the second top number to get a different nth item
SQL server only (I think) but should work on older versions that do not support ROW_NUMBER().
~ Answered on 2008-08-19 17:28:55
Verify it on SQL Server:
Select top 10 * From emp EXCEPT Select top 9 * From emp
This will give you 10th ROW of emp table!
~ Answered on 2014-10-16 10:59:04
1 small change: n-1 instead of n.
select * from thetable limit n-1, 1
~ Answered on 2008-08-19 19:25:43
Contrary to what some of the answers claim, the SQL standard is not silent regarding this subject.
Since SQL:2003, you have been able to use "window functions" to skip rows and limit result sets.
And in SQL:2008, a slightly simpler approach had been added, using
OFFSET skip ROWS FETCH FIRST n ROWS ONLY
Personally, I don't think that SQL:2008's addition was really needed, so if I were ISO, I would have kept it out of an already rather large standard.
~ Answered on 2008-09-03 22:39:36
Select n' th record from top
SELECT * FROM ( SELECT ID, NAME, ROW_NUMBER() OVER(ORDER BY ID) AS ROW FROM TABLE ) AS TMP WHERE ROW = n
select n' th record from bottom
SELECT * FROM ( SELECT ID, NAME, ROW_NUMBER() OVER(ORDER BY ID DESC) AS ROW FROM TABLE ) AS TMP WHERE ROW = n
~ Answered on 2014-02-19 04:17:16
When we used to work in MSSQL 2000, we did what we called the "triple-flip":
DECLARE @InnerPageSize int DECLARE @OuterPageSize int DECLARE @Count int SELECT @Count = COUNT(<column>) FROM <TABLE> SET @InnerPageSize = @PageNum * @PageSize SET @OuterPageSize = @Count - ((@PageNum - 1) * @PageSize) IF (@OuterPageSize < 0) SET @OuterPageSize = 0 ELSE IF (@OuterPageSize > @PageSize) SET @OuterPageSize = @PageSize DECLARE @sql NVARCHAR(8000) SET @sql = 'SELECT * FROM ( SELECT TOP ' + CAST(@OuterPageSize AS nvarchar(5)) + ' * FROM ( SELECT TOP ' + CAST(@InnerPageSize AS nvarchar(5)) + ' * FROM <TABLE> ORDER BY <column> ASC ) AS t1 ORDER BY <column> DESC ) AS t2 ORDER BY <column> ASC' PRINT @sql EXECUTE sp_executesql @sql
It wasn't elegant, and it wasn't fast, but it worked.
~ Answered on 2008-08-19 17:33:44
In Oracle 12c, You may use
OFFSET..FETCH..ROWS option with
For example, to get the 3rd record from top:
SELECT * FROM sometable ORDER BY column_name OFFSET 2 ROWS FETCH NEXT 1 ROWS ONLY;
~ Answered on 2018-02-05 12:43:42
select * from (select foo from bar order by foo) where ROWNUM = x
~ Answered on 2008-08-19 18:51:29
Here is a fast solution of your confusion.
SELECT * FROM table ORDER BY `id` DESC LIMIT N, 1
Here You may get Last row by Filling N=0, Second last by N=1, Fourth Last By Filling N=3 and so on.
This is very common question over the interview and this is Very simple ans of it.
Further If you want Amount, ID or some Numeric Sorting Order than u may go for CAST function in MySQL.
SELECT DISTINCT (`amount`) FROM cart ORDER BY CAST( `amount` AS SIGNED ) DESC LIMIT 4 , 1
Here By filling N = 4 You will be able to get Fifth Last Record of Highest Amount from CART table. You can fit your field and table name and come up with solution.
~ Answered on 2012-05-17 09:29:27
For example, if you want to select every 10th row in MSSQL, you can use;
SELECT * FROM ( SELECT ROW_NUMBER() OVER (ORDER BY ColumnName1 ASC) AS rownumber, ColumnName1, ColumnName2 FROM TableName ) AS foo WHERE rownumber % 10 = 0
Just take the MOD and change number 10 here any number you want.
~ Answered on 2011-12-30 08:41:20
That will limit the results to one result starting at result n.
~ Answered on 2008-08-19 17:14:05
For SQL Server, a generic way to go by row number is as such:
SET ROWCOUNT @row [email protected] = the row number you wish to work on.
set rowcount 20 --sets row to 20th row select meat, cheese from dbo.sandwich --select columns from table at 20th row set rowcount 0 --sets rowcount back to all rows
This will return the 20th row's information. Be sure to put in the rowcount 0 afterward.
~ Answered on 2009-06-22 17:00:08
For SQL server, the following will return the first row from giving table.
declare @rowNumber int = 1; select TOP(@rowNumber) * from [dbo].[someTable]; EXCEPT select TOP(@rowNumber - 1) * from [dbo].[someTable];
You can loop through the values with something like this:
WHILE @constVar > 0 BEGIN declare @rowNumber int = @consVar; select TOP(@rowNumber) * from [dbo].[someTable]; EXCEPT select TOP(@rowNumber - 1) * from [dbo].[someTable]; SET @constVar = @constVar - 1; END;
~ Answered on 2018-06-20 17:48:04
LIMIT n,1 doesn't work in MS SQL Server. I think it's just about the only major database that doesn't support that syntax. To be fair, it isn't part of the SQL standard, although it is so widely supported that it should be. In everything except SQL server LIMIT works great. For SQL server, I haven't been able to find an elegant solution.
~ Answered on 2008-08-19 17:18:06
Here's a generic version of a sproc I recently wrote for Oracle that allows for dynamic paging/sorting - HTH
-- p_LowerBound = first row # in the returned set; if second page of 10 rows, -- this would be 11 (-1 for unbounded/not set) -- p_UpperBound = last row # in the returned set; if second page of 10 rows, -- this would be 20 (-1 for unbounded/not set) OPEN o_Cursor FOR SELECT * FROM ( SELECT Column1, Column2 rownum AS rn FROM ( SELECT tbl.Column1, tbl.column2 FROM MyTable tbl WHERE tbl.Column1 = p_PKParam OR tbl.Column1 = -1 ORDER BY DECODE(p_sortOrder, 'A', DECODE(p_sortColumn, 1, Column1, 'X'),'X'), DECODE(p_sortOrder, 'D', DECODE(p_sortColumn, 1, Column1, 'X'),'X') DESC, DECODE(p_sortOrder, 'A', DECODE(p_sortColumn, 2, Column2, sysdate),sysdate), DECODE(p_sortOrder, 'D', DECODE(p_sortColumn, 2, Column2, sysdate),sysdate) DESC )) WHERE (rn >= p_lowerBound OR p_lowerBound = -1) AND (rn <= p_upperBound OR p_upperBound = -1);
~ Answered on 2008-08-19 17:19:01
But really, isn't all this really just parlor tricks for good database design in the first place? The few times I needed functionality like this it was for a simple one off query to make a quick report. For any real work, using tricks like these is inviting trouble. If selecting a particular row is needed then just have a column with a sequential value and be done with it.
~ Answered on 2008-08-19 19:06:57
I'm a bit late to the party here but I have done this without the need for windowing or using
WHERE x IN (...)
SELECT TOP 1 --select the value needed from t1 [col2] FROM ( SELECT TOP 2 --the Nth row, alter this to taste UE2.[col1], UE2.[col2], UE2.[date], UE2.[time], UE2.[UID] FROM [table1] AS UE2 WHERE UE2.[col1] = ID --this is a subquery AND UE2.[col2] IS NOT NULL ORDER BY UE2.[date] DESC, UE2.[time] DESC --sorting by date and time newest first ) AS t1 ORDER BY t1.[date] ASC, t1.[time] ASC --this reverses the order of the sort in t1
It seems to work fairly fast although to be fair I only have around 500 rows of data
This works in MSSQL
~ Answered on 2020-11-20 15:49:56
T-SQL - Selecting N'th RecordNumber from a Table
select * from (select row_number() over (order by Rand() desc) as Rno,* from TableName) T where T.Rno = RecordNumber Where RecordNumber --> Record Number to Select TableName --> To be Replaced with your Table Name
For e.g. to select 5 th record from a table Employee, your query should be
select * from (select row_number() over (order by Rand() desc) as Rno,* from Employee) T where T.Rno = 5
~ Answered on 2010-11-19 19:02:35
Nothing fancy, no special functions, in case you use Caché like I do...
SELECT TOP 1 * FROM ( SELECT TOP n * FROM <table> ORDER BY ID Desc ) ORDER BY ID ASC
Given that you have an ID column or a datestamp column you can trust.
~ Answered on 2015-10-01 13:16:54
SELECT top 1 * FROM table_name WHERE column_name IN ( SELECT top N column_name FROM TABLE ORDER BY column_name ) ORDER BY column_name DESC
I've written this query for finding Nth row. Example with this query would be
SELECT top 1 * FROM Employee WHERE emp_id IN ( SELECT top 7 emp_id FROM Employee ORDER BY emp_id ) ORDER BY emp_id DESC
~ Answered on 2015-01-29 09:09:46
In Sybase SQL Anywhere:
SELECT TOP 1 START AT n * from table ORDER BY whatever
Don't forget the ORDER BY or it's meaningless.
~ Answered on 2008-08-19 19:06:59
SELECT * FROM emp a WHERE n = (SELECT COUNT( _rowid) FROM emp b WHERE a. _rowid >= b. _rowid);
~ Answered on 2009-06-08 17:10:55
Most suitable answer I have seen on this article for sql server
WITH myTableWithRows AS ( SELECT (ROW_NUMBER() OVER (ORDER BY myTable.SomeField)) as row,* FROM myTable) SELECT * FROM myTableWithRows WHERE row = 3
~ Answered on 2019-11-22 20:52:46
WITH r AS ( SELECT TOP 1000 * FROM emp ) SELECT * FROM r EXCEPT SELECT TOP 999 FROM r
This will give the 1000th row in SQL Server.
~ Answered on 2020-11-24 22:42:48
If you want to look at native functionalities: MySQL, PostgreSQL, SQLite, and Oracle (basically SQL Server doesn't seem to have this function) you could ACTUALLY use the NTH_VALUE window function. Oracle Source: Oracle Functions: NTH_VALUE
I've actually experimented with this in our Oracle DB to do some comparing of the first row (after ordering) to the second row (again, after ordering). The code would look similar to this (in case you don't want to go to the link):
SELECT DISTINCT dept_id , NTH_VALUE(salary,2) OVER (PARTITION BY dept_id ORDER BY salary DESC RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS "SECOND HIGHEST" , NTH_VALUE(salary,3) OVER (PARTITION BY dept_id ORDER BY salary DESC RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS "THIRD HIGHEST" FROM employees WHERE dept_id in (10,20) ORDER BY dept_id;
I've found it quite interesting and I wish they'd let me use it.
~ Answered on 2019-12-04 15:47:20
This is how I'd do it within DB2 SQL, I believe the RRN (relative record number) is stored within the table by the O/S;
SELECT * FROM ( SELECT RRN(FOO) AS RRN, FOO.* FROM FOO ORDER BY RRN(FOO)) BAR WHERE BAR.RRN = recordnumber
~ Answered on 2016-11-18 15:12:02
It seems to me that, to be efficient, you need to 1) generate a random number between 0 and one less than the number of database records, and 2) be able to select the row at that position. Unfortunately, different databases have different random number generators and different ways to select a row at a position in a result set - usually you specify how many rows to skip and how many rows you want, but it's done differently for different databases. Here is something that works for me in SQLite:
select * from Table limit abs(random()) % (select count(*) from Words), 1;
It does depend on being able to use a subquery in the limit clause (which in SQLite is LIMIT <recs to skip>,<recs to take>) Selecting the number of records in a table should be particularly efficient, being part of the database's meta data, but that depends on the database's implementation. Also, I don't know if the query will actually build the result set before retrieving the Nth record, but I would hope that it doesn't need to. Note that I'm not specifying an "order by" clause. It might be better to "order by" something like the primary key, which will have an index - getting the Nth record from an index might be faster if the database can't get the Nth record from the database itself without building the result set.
~ Answered on 2017-07-17 06:33:46
select * from (select * from ordered order by order_id limit 100) x order by x.order_id desc limit 1;
First select top 100 rows by ordering in ascending and then select last row by ordering in descending and limit to 1. However this is a very expensive statement as it access the data twice.
~ Answered on 2017-06-02 20:26:39
unbelievable that you can find a SQL engine executing this one ...
WITH sentence AS (SELECT stuff, row = ROW_NUMBER() OVER (ORDER BY Id) FROM SentenceType ) SELECT sen.stuff FROM sentence sen WHERE sen.row = (ABS(CHECKSUM(NEWID())) % 100) + 1
~ Answered on 2009-03-06 13:30:06