I'm trying to select next 20 rows after top 10 rows.
select TOP 20 *
from memberform
where Row_Number over(10)
You need to use something like a CTE (Common Table Expression) and a ROW_NUMBER to define row numberings for your data set - then select from that numbered CTE for the set of rows you want:
;WITH PagingCte AS
(
SELECT
(list of columns),
RowNum = ROW_NUMBER() OVER (ORDER BY -some-column-of-yours-)
FROM
dbo.memberform
)
SELECT
(list of columns)
FROM
PagingCte
WHERE
RowNum BETWEEN 10 AND 29
In the inner ROW_NUMBER() window function, you need to define an ordering which defines how the rows are numbered (order by date, or by ID, or whatever makes sense for you).
Without an explicit ordering, there is no next 20 after the first 10 to be had..
do you mean offset clause ?
OFFSET excludes the first set of records.
OFFSET can only be used with an ORDER BY clause.
OFFSET with FETCH NEXT returns a defined window of records.
OFFSET with FETCH NEXT is great for building pagination support.
The general syntax to exclude first n records is:
SELECT column-names
FROM table-name
ORDER BY column-names
OFFSET n ROWS
Please refer to http://www.dofactory.com/sql/order-by-offset-fetch
WITH T AS
(
SELECT TOP 30 name,
row_number() OVER (ORDER BY id) AS RN
FROM memberform
ORDER BY id
)
SELECT
MAX(CASE WHEN RN <=10 THEN name END) AS Col1,
MAX(CASE WHEN RN > 10 THEN name END) AS Col2
FROM T
GROUP BY RN % 10
Related
Since I cant use rownum in the query, how can i use rowid to get result from 2nd row until 4th row using rowid or other possible solution apart from rownum.
Here is my current query where it will retrieve 2nd and 4th row:
SELECT * FROM Record a
WHERE
2 = (SELECT COUNT (rowid)
FROM Record b
WHERE a.rowid >= b.rowid)
UNION
SELECT * FROM Record a
WHERE
4 = (SELECT COUNT (rowid)
FROM Record c
WHERE a.rowid >= c.rowid);
Maybe there are other better ways to do it? TQ
If you can't use rownum, then use row_number():
SELECT a.*
FROM (SELECT a.*, ROW_NUMBER() OVER (ORDER BY rowid) as seqnum
FROM Record a
) a
WHERE seqnum BETWEEN 2 and 4;
Note: The ?? is for an ordering column. SQL tables represent unordered sets, so there is no concept of a first row or a second row, except in reference to an ordering column. You can use rowid for this purpose.
In Oracle 12c, you would use OFFSET/FETCH:
SELECT a.*
FROM Record a
OFFSET 1 ROWS
FETCH FIRST 3 ROWS ONLY;
I should point out that you can use rownum. You just can't do:
SELECT a.*
FROM Record a
WHERE rownum BETWEEN 2 and 4;
You can use it in a subquery:
SELECT a.*
FROM (SELECT a.*, rownum as seqnum
FROM Record a
) a
WHERE seqnum BETWEEN 2 and 4;
Do note that without an ORDER BY, there is no guarantee that the results come back in any order, including rowid order.
If you want to avoid rownum and row_number, use sum:
select *
from (
select sum(1) over ( order by rowid /* or whatever you need */ ) as rn,
r.*
from record
)
where rn between 2 and 4
The trick is only in the fact that here sum(1) gives the same thing than count(1) or count(rowid) or whatever count on a not null value, and this is the same thing than counting the rows with row_number or rownum.
In this way you use the sum to compute a row_number, without explicitly writing 'row_number' or 'rownum'.
SQL> create table testTab(x) as ( select level from dual connect by level <= 6);
Table created.
SQL> select t.*,
2 count(1) over (order by rowid desc) as count,
3 sum(1) over (order by rowid desc) as sum,
4 row_number() over (order by rowid desc) as rowNumber
5 from testTab t;
X COUNT SUM ROWNUMBER
---------- ---------- ---------- ----------
6 1 1 1
5 2 2 2
4 3 3 3
3 4 4 4
2 5 5 5
1 6 6 6
The external query simply applies the filter.
With Oracle 12c, you can now easily do row limiting. In your scenario you can do something like this:
SELECT *
FROM RECORD
OFFSET 1 ROWS FETCH NEXT 1 ROWS ONLY
UNION
SELECT *
FROM RECORD
OFFSET 3 ROWS FETCH NEXT 1 ROWS ONLY
If I have two columns - an ID field and a score field that can take 10 possible values, how can I select 5 random rows per ID? I know I can select 5 random rows from a table by using the following:
select *, rand() as idx
from mytable
order by idx fetch first 5 rows only
but how about 5 rows per ID?
You can do this using row_number():
select t.*
from (select t.*,
row_number() over (partition by idx order by rand()) as seqnum
from mytable t
) t
where seqnum <= 5;
I have thousands of groups in a table, something like :
1..
1..
2..
2..
2..
2..
3..
3..
.
.
.
10000..
10000..
How can i make a select that give me the Top 3 groups each time.
I Want something like select Top 3 from rows , but it have to return the first three groups not the first three rows.
You can try this :
;with cte as (
select distinct groupId from mytable order by groupid
)
select * from mytable where TheGroupId in (select top 3 groupdid from cte)
You can use DENSE_RANK to assign a number to each group. All members of the same group will have the same number. Then in an outer query, select top 3 groups:
SELECT *
FROM (SELECT *, DENSE_RANK() OVER (ORDER BY id) AS rnk
FROM mytable ) t
WHERE t.rnk <= 3
The above query assumes that id is the column used to group records together.
SQL Fiddle Demo
Use Ranking function Row_Number() :
SELECT *
FROM (SELECT *,
Row_number()
OVER(
partition BY GroupId
ORDER BY GroupId) AS [rn]
FROM YourTable) t
WHERE rn <= 3
Check this MSDN doc for details of all ranking functions.
There is a sql TOP statement that does this
SELECT TOP number|percent column_name(s) FROM table_name;
a description of what it does and how it is used in alternative sql statements for example for mysql and ms access can be found here: http://www.w3schools.com/sql/sql_top.asp
My bad i misread your question, this will return the top rows not groups, could you explain what you are trying to do in more detail?
SELECT *
FROM
(SELECT *
,ROW_NUMBER() OVER (PARTITION BY [Group] ORDER BY [Group] ASC)rn
FROM TableName
)A
WHERE rn <= 3
I have a table that I want to calculate the average of one column but only for the last 10 rows.
SELECT AVG(columnName) as avg FROM tableName
I cannot apply top directly since this query only returns one row. I need a way to get the latest 10 rows and do the average on them.
Try this:
SELECT AVG(columnName) FROM
(SELECT TOP 10 columnName FROM tableName ORDER BY ColumnWhichHoldsOrder DESC) A
select avg(columnName)
from (
select columnName,
row_number() over (order by some column desc) as rn
from tableName
) t
where rn <= 10;
How do I retrieve the second highest value from a table?
select max(val) from table where val < (select max(val) form table)
In MySQL you could for instance use LIMIT 1, 1:
SELECT col FROM tbl ORDER BY col DESC LIMIT 1, 1
See the MySQL reference manual: SELECT Syntax).
The LIMIT clause can be used to constrain the number of rows returned by the SELECT statement. LIMIT takes one or two numeric arguments, which must both be nonnegative integer constants (except when using prepared statements).
With two arguments, the first argument specifies the offset of the first row to return, and the second specifies the maximum number of rows to return. The offset of the initial row is 0 (not 1):
SELECT * FROM tbl LIMIT 5,10; # Retrieve rows 6-15
select top 2 field_name from table_name order by field_name desc limit 1
SELECT E.lastname, E.salary FROM employees E
WHERE 2 = (SELECT COUNT(*) FROM employess E2
WHERE E2.salary > E.salary)
Taken from here
This works in almost all Dbs
Select Top 1 sq.ColumnToSelect
From
(Select Top 2 ColumnToSelect
From MyTable
Order by ColumnToSelect Desc
)sq
Order by sq.ColumnToSelect asc
Cool, this is almost like Code Golf.
Microsoft SQL Server 2005 and higher:
SELECT *
FROM (
SELECT
*,
row_number() OVER (ORDER BY var DESC) AS ranking
FROM table
) AS q
WHERE ranking = 2
Try this
SELECT * FROM
(SELECT empno, deptno, sal,
DENSE_RANK() OVER (PARTITION BY deptno ORDER BY sal DESC NULLS LAST) DENSE_RANK
FROM emp)
WHERE DENSE_RANK = 2;
This works in both Oracle and SQL Server.
Try this
SELECT TOP 1 Column FROM Table WHERE Column < (SELECT MAX(Column) FROM Table)
ORDER BY Column DESC
SELECT TOP 1 Column FROM (SELECT TOP <n> Column FROM Table ORDER BY Column DESC)
ORDER BY ASC
change the n to get the value of any position
Maybe:
SELECT * FROM table ORDER BY value DESC LIMIT 1, 1
one solution would be like this:
SELECT var FROM table ORDER BY var DESC LIMIT 1,1