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.

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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 in a ResultSet

Hello,
I'm an intern and I'm trying to get the number of rows from result set in oracle using rs.last() and rs.beforeFirst() methods
but I got an error. Could Below is my sample code:
import java.sql.*;
public class SarueckConnect {
public static void main(String[] args) {
Connection con = null;
Statement stmt = null;
ResultSet re = null;
String[] ParamArray;
ParamArray = new String[24];
//Properties logon;
try {
Class.forName("oracle.jdbc.driver.OracleDriver"); //Loading the Oracle Driver.
con = DriverManager.getConnection
("jdbc:oracle:thin:@258.8.159.215:1521:test_DB","data","data"); //making the connection DB.
stmt = con.createStatement ();// Sending a query string to the database
//stmt.executeUpdate("UPDATE test_table set steuk = 6 WHERE steuk = 5");
ResultSet rs = stmt.executeQuery("SELECT mandt,kokrs,werks,arbpl,aufnr,vornr,ile01,"+
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"kostl,pernr,rueckid FROM test_table where steuk =6");
//Print the result out.
rs.last(); //This is the line which gives an error.
int rows = rs.getRow();
rs.beforeFirst();// I presume this is wrong to.
ParamArray = new String[24*rows];
int counter=0;
while (rs.next()) {
for (int i = 1; i <= 24; i++){
ParamArray[i-1+(counter*24)] = rs.getString(i);
System.out.print(rs.getString(i) + '\t');
System.out.println();
counter++;
} catch(Exception e) {
e.printStackTrace();
} finally {
try
if(stmt != null) stmt.close();
if(con != null) con.close();
} catch (Exception exception) {
exception.printStackTrace();
TryBapi sap = new TryBapi(ParamArray);
}When I run the code I do have the following ERROR Message:
java.sql.SQLException: Invalid operation for forward only resultset : last
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:179)
at oracle.jdbc.driver.BaseResultSet.last(BaseResultSet.java:91)
at SarueckConnect.main(SarueckConnect.java:28)Please could any body Help me out here to figure out how to correct this?
Any Help would be highly apprecited.

make your result set scrollable...Not such a good idea. With Oracle, the JDBC driver will read and cache all the ResultSet in memory (with other DBMSs/drivers the behavior will probably be different, but you will still have some unnecessary overhead).
You can do the caching yourself if you think it's worth it. If the piece of code you posted is why you need this for, then use a List or Vector and you won't need to know the size upfront.
Alin,
The jTDS Project.

Getting the no. of rows returned from the resultset

Could somebody tell how can I get the count of rows from the resultset object.
Thanks a lot in advance

hmmm 20,710 topics and 69,000 odd posts and no one has EVER asked this question before.. it's a miracle....
or maybe it has been asked and dealt with approx... 11,000 times.
here is a discussion from 1998 for example http://forum.java.sun.com/thread.jsp?forum=48&thread=83958

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

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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.

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Thanks,
Jon.

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How do I get the number of rows in a ResultSet?

I checked the API, but didn't find a method that does this.

You could try calling last() then getRow() to get the
no of rows ...You probably need a scrollable resultset to do this, so that you can
rewind back to the start and read the data in.
I imagine you want to get a count, to size an array, before reading in the data ? Why not load it in an arraylist, then convert to an array afterwards ?
regards,
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http://download.oracle.com/docs/cd/E17556_01/doc/user.40/e15517/ui.htm#CHDDGGEG
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How do you return the number of Rows in a ResultSet??

How do you return the number of Rows in a ResultSet? It's easy enough to do in the SQL query using COUNT(*) but surely JDBC provides a method to return the number of rows.
The ResultSetMetaData interface provides a method for counting the number of columns but nothing for the rows.
Thanks

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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 ......)
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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.

Trying to find the number of rows in a ResultSet

I am trying to find the number of rows in a ResultSet, using the following code:
rs = st.executeQuery(query);
rs.last(); // to move the cursor to the last row
System.out.println(rs.getRow());
However, I am getting this error:
java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Unsupported method: ResultSet.last
Whats going wrong??

praveen_potru wrote:
You might have not used scrollable result set..
Try like this:
stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);rs = stmt.executeQuery(sqlString);
// Point to the last row in resultset.
rs.last();
// Get the row position which is also the number of rows in the ResultSet.
int rowcount = rs.getRow();
System.out.println("Total rows for the query: "+rowcount);
cheersAnd I hope the OP would read it because the thread is a year old.

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Hi all,
When I launch a report from forms then sometimes there are data in the report and sometimes there are no data. And the problem is that when there are no data then the frame containing the repeating frame is still displaying and a blank page displays on the report.
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Thank you very much indeed.

Dear Friend,
You can achieve this. Define a summary column (say cnt). Select summary type as "COUNT". select any one of columns that are getting displayed in your repeating frame as summary column and provide "reset at" group name (or set this to report if you are defining this field at report level) . This "cnt" variable will contain how many records that will be fetched for your repeating frame (i.e. Group of Repeating frame). You can use this "CNT" variable in your format trigger.
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Manish Trivedi

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When i open a database cursor i do not know how much rows are stored in the cursor. To solve this problem i have to send a 'select count(1) ...' to get the number of rows before i set up the cursor. I think that this is not very clever and could possibly cause performance problems. But i need the num of rows to show the percentage of processed rows. Is there any other way to get the num of rows? May be by checking the cursor directly?
Please help!
Thanx a lot

In order to find out how may rows are going to be processed, oracle has to visit every row. So with a cursor, there is no property that will accurately reflect the number of rows until you get to the last one. That said, you could use
select count(*) over() as row_count, <rest of your columns> FROM <your table>
which will give you the total row count agaist each row in the result set. There are performance penalties involved but they will be less than issuing the query twice, once to get the count and once to get the rows.
Have a look on asktom for some very usefull info about all this.
HTH

How to get the number of rows written to the header of the spool file.

Hi
I need to create a header line for the spool file .
the header line should include fixed length values .
The header should include the number of records found in the table with a maximum begin date (begin_date is the column of the table)
To get the header in the spool file , i wrote a select query has :-
--SPOOL 'C:\Documents and Settings\abc\Desktop\output.TXT'
select 'W'||to_char(sysdate,'MM/DD/YYYYMi:HH:SS')||lpad(max(rownum),9,'000000000') ||'R'||max(to_char(school_from_date,'MM/DD/YYYY')) ||
rpad(' ',76,' ')
from dad.school
group by sysdate;
SPOOL OFF
which gets me all the rows in the table , but i only want the rows with the latest school_begin_date .
how can i achieve that ...
I know that a subquery should be written in the from clause to get the number of rows found with a maximum school_begin_date.
select 'W'||to_char(sysdate,'MM/DD/YYYYMi:HH:SS')||lpad(max(rownum),9,'000000000') ||'R'||max(to_char(school_from_date,'MM/DD/YYYY')) ||
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I NEED HELP ..IN GETTING THE ROWNUM JUST FOR THE LATEST BEGIN_DATE ?
PLS HELP ME IN WRITING THE QUERY .
THANKS IN ADVANCE .

Try this:
select 'W'||to_char(sysdate,'MM/DD/YYYYMi:HH:SS')||lpad(max(rownum),9,'000000000')||'R'||max(to_char(school_from_date,'MM/DD/YYYY')) || rpad(' ',76,' ')
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Getting the number of rows returned from ResultSet

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