Need to limit number of rows returned by a query
Hi. Is there a way to limit the rowsets returned to me in a query? I need to get the first 100, then the next hundred, etc until there are no more rows left to retrieve. Someone told me that I should use a cursor to do this. Does anyone have a specific example? Can this be done with a combination of SQL/JDBC?
Thanks in advance...bbetta
null
if you are talking about limiting the number of rows to be returned to the calling program to a managable number of rowa ...
for example the result set size would be 5000 rows and you want to get them in batches of 50 or 100 ..
see the attached link :
JDBC Code Templates
http://technet.oracle.com/sample_code/tech/java/sqlj_jdbc/htdocs/templates.htm#BatchSize
if you want the server side transaction to only return the first 50 or 100 rows even though the result set has more ... then
another approach is required -- possibly as suggested above ...
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Number of rows returned in a query
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Thanks,
YonNo.
Because rows are not all returned until you start interating.
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How to get number of rows return in SELECT query
i'm very new in java, i have a question:
- How to get number of rows return in SELECT query?
(i use SQL Server 2000 Driver for JDBC and everything are done, i only want to know problems above)
Thanks.make the result set scroll insensitve, do rs.last(), get the row num, and call rs.beforeFirst(), then you can process the result set like you currently do.
String sql = "select * from testing";
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rs.beforeFirst();~Tim
NOTE: Ugly, but does the trick. -
How to restrict number of rows returned in a query
Hi frnds,
I'd like to restrict number of rows returned by my query to some 10 rows. how to do that.When I try doing with the rownum<10 its giving results for a particular dept and that too some 6 rows only...btw I'm grouping my table and includes joins from many a table and am ordering the table results by a column.. How to do this..776317 wrote:
Hi frnds,
I'd like to restrict number of rows returned by my query to some 10 rows. how to do that.When I try doing with the rownum<10 its giving results for a particular dept and that too some 6 rows only...btw I'm grouping my table and includes joins from many a table and am ordering the table results by a column.. How to do this..
TELL ME HOW MANY ROWS YOU HAVE IN TABLE?
Because you have only *6 rows* in you column, if you less than 10 rows then it displays only containied/exist rows. nothing much
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Limit number of rows returned in Toad
Hi,
I use toad to query a database, in fact, its a data warehouse and each time my query returns a huge number of rows and I have to wait for quite some time. Is there a way of getting only a few rows at a time. I mean, I want to see the complete data returned by in a piecemeal manner, say it fetches me the first 30 rows and I keep seeing this data while it keeps getting the next 30.
Any suggestions?
Thanks in advance,
RajeshThe first query will give you a random set of 100 rows from your table. There is no such thing as the "first 100 rows" without an order by in the inner query. The secons query will return nothing.
SQL> SELECT * FROM (
2 SELECT indv_id FROM indv_t)
3* WHERE rownum > 100 and rownum < 200;
no rows selectedA close approximation of this query that does return rows is:
SQL> SELECT * FROM (
2 SELECT indv_id,rownum rn FROM indv_t)
3* WHERE rn > 100 and rn < 200;
INDV_ID RN
1040 101
1057 102
1073 103
2055 197
2063 198
2071 199
99 rows selected.The only correct, repeatable, efficient way to page data is something like:
SELECT * FROM
SELECT *, rownum rn FROM
your query here WITH AN ORDER BY
WHERE rn <= :max_value
WHERE rn >= :min_valueOracle will not guarantee that the same query will return the rows in the same order for every execution without an ORDER BY clause. There are dozens of factors that can influence the query path chosen by the optimizer, and therefore the order of the rows returned. As the optimizer gets more complex (and smarter?), and Oracle adds new acces paths, I xan only assume that the number of factors influencing the access path will continue to grow.
In short, if you want to talk about first and last rows, you need to sort them first.
TTFn
John -
Output the number of rows returned in a query
How do I find out the number of rows that are returned in a query?
COUNT function I guess can only be used when there is only one table involved. How do I do it for multi table query like JOIN?
For example
SELECT emp.first_name, emp.last_name, jobs.age FROM employees emp, jobs
WHERE emp.employee_id=jobs.employee_idHi,
You can get the num of rows info
select count(*) from (SELECT emp.first_name, emp.last_name, jobs.age FROM employees emp, jobs
WHERE emp.employee_id=jobs.employee_id) ;
regards
Jafar
http://www.oracledbarea.blogspot.com -
Need to retrieve number of rows affected by SQL query
Hi,
I am executing some update queries in SQL in a xMII transaction. Iam using a SQL Query template for the same and I need to find out how many records were affected by the last executed statement. I have tried doing SELECT @@ROWCOUNT in a second SQL template that executes after the UPDATE SQL Query Template. However, the results are intermittent, sometimes it returns 1 row affected as expected but sometimes returns 0 rows. Can anyone help on this.
ThanksAnamika,
1) As per sql best practices use of trigger is not recommend unless you don't have any other option because usually triggers consume more resources and IO since it involves internal monitoring.
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3) The other alternative is to create a Stored Procedure but it again boils down to your authorization issue. This would be easier and better if you have authorization to create SP's. But nevertheless give it a try.
4) Lets forget about SP say that you have an Update Statement like
Update Table1 set column2 = 'abc' where Column2 = 'xyz'
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Select count(*) from Table1 where Column2 = 'abc'
The @@ROWCOUNT is powerful within t-sql with SP, cursors etc..
Hope this helps!!
Regards,
Adarsh -
Limiting number of rows returned by SQVI
I've created a query in SQVI and I need to limit the number of rows returned by the query. (I'm using the query as an exploratory tool, and it's not easy to predict how many records will be returned based on the selection fields I'm using.)
Is there any way to add a 'Maximum No. of Hits' field to the SQVI selection screen similar to what is found when using SE16?
Thanks,
BobIt's not surprising that you are confused because the documentation doesn't bother to explain what the "fetch size" actually is, it just says that setFetchSize sets it and getFetchSize gets it. As I understand it from some other documents I read about JDBC, the fetch size is a number that may be used internally by the JDBC driver. Here's an example of how I understand it (others, I know you will feel free to correct me if you disagree):
When the driver produces a result set with a very large number of records, it has to generate those records and deliver them to the system that requested them. If the database is not on the same system, then those records must all travel over the network. It could be a performance problem if you had to wait for (say) 80,000 records to travel across the network. Enter the fetch size. If you set the fetch size to 100, then the driver will bring the records across in batches of 100, as the program calls for them. Now, this buffering is transparent to your program; the driver doesn't tell you that it's getting another batch and you can't tell it to get another batch. So it is not a solution to the problem that everybody has here, namely how to display your records 10 per page and allow the user to go back and forth among those pages, like search engines do. -
Getting the number of rows returned from ResultSet
Hi,
Does anyone know a method to get the number of rows returned with a query using the Resultset class?
Thanks.Hi 281080,
If your database and JDBC driver support it, in order to use the solution that da-alexj has suggested, you need to create a 'scrollable' "ResultSet" -- the javadoc for method "createStatement()" (in class "java.sql.Connection") has more details.
However, I have found with Oracle 8.1.7.4 database and Oracle (thin) JDBC driver, that part of their implementation of the "last()" method (in class "java.sql.ResultSet") is to actually iterate through the entire "ResultSet" in order to reach the last row. If your "ResultSet" is very large (I tested it with a 100,000 row "ResultSet"), this will take a long time.
Just wanted to make you aware of that.
Of-course, this may be irrelevant to you since I didn't see any mention in your post of what database and JDBC driver you are using.
Hope this has helped you, anyway.
Good Luck,
Avi. -
Is it possible to count the rows returned from a query?
Hello,
When using JDBC is there anyway of finding out the number of
rows returned from a query before actually getting each row?
In Forms 4.5 you can use the count_query function, does anyone
know of an equivalent function or work around in JDBC and/or
SQLJ?
Thanks.
nullPasi Hmlinen (guest) wrote:
: Try
: SELECT COUNT(*) FROM the_table WHERE <conditions>;
: Hope this helps,
: Pasi
Thanks for the advice, I'm currently using SELECT COUNT(*) but
I'm looking for a more efficient way of doing it. If I SELECT
COUNT each time then I have to prepare and execute a SQL
statement each time. What I want to do it execute a single SQL
statement to return my results and somehow find out the number
of rows in the resultset without having to go back to the
database.
Gethin.
null -
Need to know how to limit the number of rows returned on Oracle
MS SQL Server has a command called 'set row count'.
We are trying to find similar one on Oracle.
What we are trying to do is that instead of using rownum in the query statement, we would like to find way to limit the number of rows returned. I understand that we can use JDBC resultSet object, but that's not what we want.
I know Oracle has one called arraysize, but this would not limit the number of rows returned either.
Pease help.
ThanksI understand that we can use JDBC resultSet object, but that's not what we want.I'm not sure which feature of ResultSet you use and which not.
But if this question has anything to do with JDBC (that's the forum where you put it), I'd recommend to use Statement.setMaxRows(). This will limit the count of rows which your statement will fetch into it's ResultSet. -
How can I limit the number of rows returned by a select stat
How can I limit the number of rows returned by a select
statement. I have a query where I return the number of stores
that are located in a given area.. I only want to return the
first twenty-five stores. In some instances there may be over
200 stores in a given location.
I know is SQL 7 that I can set the pagesize to be 25....
Anything similiar in Oracle 8i?
nullDebbie (guest) wrote:
: Chad Nale (guest) wrote:
: : How can I limit the number of rows returned by a select
: : statement. I have a query where I return the number of
: stores
: : that are located in a given area.. I only want to return the
: : first twenty-five stores. In some instances there may be
: over
: : 200 stores in a given location.
: : I know is SQL 7 that I can set the pagesize to be 25....
: : Anything similiar in Oracle 8i?
: If you are in Sql*Plus, you could add the statement
: WHERE rownum <= 25
: Used together with an appropriate ORDER BY you
: could get the first 25 stores.
Watch out. ROWNUM is run before ORDER BY so this would only
order the 25 selected
null -
Can I limit the number of rows returned on a Select?
Can I limit the number of rows returned on a Select statement? I would be using JDBC in a Java program.
Use Java prepared statements with the equivalent of this SQL*plus script:
VARIABLE n number
EXEC :n := 3;
SELECT rownum FROM all_objects WHERE rownum <= :n;
ROWNUM
1
2
3
EXEC :n := 5;
SELECT rownum FROM all_objects WHERE rownum <= :n;
ROWNUM
1
2
3
4
5 -
How do you limit the number of rows return from query?
How do you limit the number of rows return from query? Do all databases support this kind of feature?
i think the standard is limit
to get the top 30
select * from mytable LIMIT 30;returns the first 30 rows
also if you want a range
select * from mytable LIMIT 10,30;returns 30 rows starting from 10
this last one is useful for displaying ranges... something similar happens in these forums when viewing topics and messages -
Number of rows returned for a report
I want to create reports on serveral tables, the number of rows in these tables varies a lot (5, 5000, and the other one can have 10000+ rows).
In the Reports Attributes page, is there a way to set the max number of rows return to the number of rows of the table? For example, for a table that has 10000 rows now, may grow to 20000 rows in the near future. If I specify the "Max Row Count" to 20000, the number may be outgrown yet again soon. If I can specify "Max Row Count" to "Current number of rows in the table" then this problem will not happen. Can it be done?that "Max Row Count" attribute is used to limit the number of rows returned by a htmldb report region. in your case it sounds as if you want to show all available rows all the time. in that case you'd be fine to just put a very large number into that field like 4million. that way you'd always show all your rows.
hope this helps,
raj
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