Limiting the number of rows returned by SQL or ResultSet

Hello,
I'm trying to limit the number of rows that my application receives to a user-specified value. The user is asked how many accounts they want returned and I want to limit my ResultSet to this amount. I'd prefer to set up the SQL to do this if possible rather than waste time returning more records than necessary to the ResultSet.
If it's not possible to limit the SQL, how can I limit the number when processing the ResultSet?
Or, is there any way to setup a cursor in JDBC without being able to use Stored Procedures?
I'm going up against DB2 using DB2Connect.
Thanks!

It'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.

Similar Messages

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?
null

Debbie (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

How can I get the number of rows in my sql result, without a loop?

Hello,
I've a problem, I would like to get the number of rows in my sql result without make a loop like :
while (rs.next()){
int number = rs.getRow();
Is there any method to do this, on the first element?
Thx, STeF

If you want to count how many rows are in result set, I dont think you can, but you could always run a count statement for that sql
say your sql is
select field1, field2, field3
from table1, table2
where field4=field5 ......
then you can count the rows this statement returns by
select count(*) from
(say your sql is
select field1, field2, field3
from table1, table2
where field4=field5 ......)
This way you will get the count for just that sql

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

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.

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.
Thanks

I 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 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

How to get the number of rows returned by a report?

Hi,
I'm developing my first application in APEX and so far everything seems fine, except I can't figure out this very simple thing: I have a report based on a PL/SQL block returning an SQL string. I'd like to have a message (something like "X rows returned") just before the report. The closest thing I could find was "X to Y out of Z" in the pagination styles, but that's not what I want. Also I don't think running the same query to get COUNT() is wise.
Any help would be appreciated.
Thanks,
Konstantin

My guess is that it only shows the number of rows it has retrieved. I believe the defailt is for it to only retrieve 50 rows and as you page through your report it retrieves more. So this would just tell you how many rows was retireved, but probably not how many rows the report would contain if you pages to the end. Oracle doesn't really have a notion of total number of rows until the whole result set has been materialized.

Get the number of rows returned by a dataProvider

hi
I am using a [Bindable] variable that I am setting and using
as a DataProvider (coming from a web service) for a DataGrid within
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is there a way of knowing the amount of rows that the
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as I want to do a calculation to set the height of the
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Thanks,
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that only seems to count the default number of rows (height)
of the datagrid..... i.e. 7.
I need to know the number of rows being returned from the
dataProvider - i.e. the number of rows coming through the
webService from the database etc.....
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Jon.

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_id

Hi,
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

How do you change the number of rows returned by an advanced datagrid...Only displays 1000 rows....I

I am using coldfusion to query an oracle table....Query returns approximately 2000 rows, however the max rows the datagrid will display is 1000. Does anybody know how to change this...THANKS!!

Thanks so much for your answer that sounds like a good idea...
I found the answer to my initial problem...In my coldfusion I had set maxrows = 1000. So the datagrid was always returning 1000 records even when a lot more than that should have been returned...When I removed the maxrows parameter in the coldfusion code, my datagrid was now been populated with the correct number of rows...
thanks again for your help,
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Number of rows returned by the resultset is wrong

Hi All,
I have pasted the code i used for JDBC. The problem is the number of rows returned by the resultset is 5 times that of the original data. Is something wrong with my code. Can anyone pls point out the mistake I have done if any.
    public ArrayList dataBreakup(String team, int monthNo, int year) {         String sqlDataBreakup = "";         Connection con1 = null;         Statement stmt = null;         ResultSet rs = null;         ArrayList data = new ArrayList();         int noRows = 0;         Calendar cal = Calendar.getInstance();         Calendar cal2 = new GregorianCalendar(cal.get(Calendar.YEAR), monthNo, 1);         int days = cal2.getActualMaximum(cal2.DAY_OF_MONTH);         String start_date = "01-Jan-" + year;         String end_date = days + "-" + monthName[cal2.get(Calendar.MONTH)] + "-" + cal2.get(cal2.YEAR);         System.out.println("START: " + start_date);         System.out.println("END: " + end_date);         databaseConnection dbObject = new databaseConnection();         try {             con1 = dbObject.GetConnection();             stmt = con1.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);             sqlDataBreakup = "Select * from EXPENSE_STORE WHERE " +                     "team='" + team + "'AND category != 'Pending PO''s' AND ACCOUNTING_DATE " +                     "BETWEEN to_date('" + start_date + "') AND to_date('" + end_date + "')";             rs = stmt.executeQuery(sqlDataBreakup);                         ResultSetMetaData rsmd = rs.getMetaData();             int numColumns = rsmd.getColumnCount();             data.add(numColumns);             for (int i = 1; i < numColumns + 1; i++) {                 data.add(rsmd.getColumnName(i));             }                        while (rs.next()) {                                noRows++;                 for (int i = 1; i < numColumns + 1; i++) {                     switch (rsmd.getColumnType(i)) {                         case java.sql.Types.NUMERIC:                             data.add(rs.getFloat(i));                             break;                         case java.sql.Types.DATE:                             data.add(rs.getDate(i));                             break;                         default:                             data.add(rs.getString(i));                             break;                     }                                    }                     }             data.add(1, noRows);             rs.close();         } catch (SQLException SQLe) {             System.out.println("DumpData() : SQL Exception" + SQLe.getMessage());             SQLe.printStackTrace();         } catch (Exception e) {             System.out.println("DumpData() : Other Exception");             e.printStackTrace();         } finally {             dbObject.CloseConnection(con1);         }         return data;     }
Thanks
Cheers N...

Only thing i can say is
try the following
replace your function by this one and tell us the console output of the same
public ArrayList dataBreakup(String team, int monthNo, int year) {
        String sqlDataBreakup = "";
        Connection con = null;
        ArrayList data = new ArrayList();
        int noRows = 0;
        Calendar cal = Calendar.getInstance();
        Calendar cal2 = new GregorianCalendar(cal.get(Calendar.YEAR), monthNo, 1);
        int days = cal2.getActualMaximum(cal2.DAY_OF_MONTH);
        String start_date = "01-Jan-" + year;
        String end_date = days + "-" + monthName[cal2.get(Calendar.MONTH)] + "-" + cal2.get(cal2.YEAR);
        System.out.println("START: " + start_date);
        System.out.println("END: " + end_date);
        System.out.println("START: " + start_date);
        System.out.println("END: " + end_date);
        databaseConnection dbObject = new databaseConnection();
        try {
            con = dbObject.GetConnection();
            sqlDataBreakup = "Select * from EXPENSE_STORE WHERE " +
                    "team = '"+team+"' AND category != 'Pending PO''s' AND ACCOUNTING_DATE " +
                    "BETWEEN to_date('"+start_date+"') AND to_date('"+end_date+"')";
               System.out.println("-----------sql starts---------------");
               System.out.println(sqlDataBreakup);
               System.out.println("-----------sql ends---------------");
            PreparedStatement pstmt = con.prepareStatement(sqlDataBreakup);
               pstmt.setString(1, team);
            pstmt.setString(2, start_date);
            pstmt.setString(3, end_date);
            ResultSet rs = pstmt.executeQuery();
            ResultSetMetaData rsmd = rs.getMetaData();
            int numColumns = rsmd.getColumnCount();
            data.add(numColumns);
            for (int i = 1; i < numColumns + 1; i++) {
                data.add(rsmd.getColumnName(i));
            while (rs.next()) {
                noRows++;
                for (int i = 1; i < numColumns + 1; i++) {
                    switch (rsmd.getColumnType(i)) {
                        case java.sql.Types.NUMERIC:
                            data.add(rs.getFloat(i));
                            break;
                        case java.sql.Types.DATE:
                            data.add(rs.getDate(i));
                            break;
                        default:
                            data.add(rs.getString(i));
                            break;
            //data.add(1, noRows);
               System.out.println("no of Rows : " +noRows );
        } catch (SQLException SQLe) {
            System.out.println("DumpData() : SQL Exception" + SQLe.getMessage());
            SQLe.printStackTrace();
        } catch (Exception e) {
            System.out.println("DumpData() : Other Exception");
            e.printStackTrace();
        } finally {
            dbObject.CloseConnection(con);
        return data;
    }and try running the sql printed on the screen in your db and then let us know the result.
in this code i have removed some of your code in order to simplify the problem.

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,
Bob

It'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.

Question about number of rows returned in PL/SQL , SQL

The Child Table has 3 Million plus records, but the loaded table only brings back
approximately 1.2 Million records. Is there anything on the Oracle side that would limit the number of rows returned.

Would it be possible to post a test case that explains what you're seeing? It sounds like you are indicating that
SELECT COUNT(*) FROM <<some table>>returns 3 million rows. When some process goes to load a Teradata table by extracting all the information from this Oracle table, the Teradata table ends up with only 1.2 million rows. Is that correct?
If so,
- What is the ETL process?
- Is it possible that the ETL process is encountering an error midway through?
- Is it possible that the ETL process is extracting a subset of the data through a WHERE clause?
- Is the ETL process logging in as the same Oracle user you're using to do the COUNT(*)?
Justin

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 ...

Limiting the number of rows returned by SQL or ResultSet

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