Getting the first row from a ResultSet??

I have a query that returns a set of values but am interested only in the first value.How can I get that. I tried to use getArray method but that gives a "java.sql.SQLException: Exhausted Resultset".
Any suggestions??

I think I'm having the same problem with you.
this is my method:
private Vector getData( ResultSet rs){
String str = "";
try{
while( rs.next() ){
str = rs.getString( 1 );
rows.addElement( str );
}catch( SQLException sqlex ){
sqlex.printStackTrace();
return rows;
I don' t know if you meant this.hoping this can help you

Similar Messages

Trying to get the last row from a resultset

Hi,
I'm trying to do a query to postgreSQL and have it return the last updated value, (last row).
My prepared statement is returning the correct results, but i'm having a problem getting the latest value.
I'm using a comboBox to drive a textfield, to load the last entered values in depending on which item in the comboBox is selected.
I've tried a variety of things and most seem to return the first row, not showing the updated values.
Or, if it does work, it takes to long to load, and i get an error.
here is the working code;
Object m = machCBX.getSelectedItem():
try { PreparedStatment last = conn.prepareStatement("SELECT part, count FROM production WHERE machine = ?",
ResultSet.TYPE_SCROLL_INSENSITIVE, //tried both INSENSITIVE and SENSITIVE
ResultSet.CONCUR_READ_ONLY);
last.setString(1, String.valueOf(m));
rs. = last.executeQuery();
if(rs.isAfterLast) == false ) {
rs.afterLast();
while(rs.previous()) {
String p = rs.getString("part");
int c = rs.getInt("count");
partJTX.setText(p);
countJTX.setText(c);
}this grabs values, but they are not the last entered values.
Now if i try to use rs.last() it returns the value i'm looking for but takes to long, and i get:
Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space I also know using ra.last() isn't the best way to go.
I'm just wondering if there is another way other than getting into vectors and row count? or am i better off to go with the later?
thanks
-PD

OK, you've got a major misunderstanding...
The relational database model is built on the storage of sets - UNORDERED sets. In other words, when you hand a database a SELECT statement without an ORDER BY clause, the database is free to return the results in any order.
Now it so happens that most databases will happen to return data retrieved by an unordered SELECT, at least for a while, in the same order that it was inserted, especially if no UPDATE or DELETE activity has occured, and no database maintenance has occured. However, eventually most tables have some operation that creates a "space" in the underlying storage, or causes a row to expand and have to be moved or extended, or something. Then the database will start returning unordered results in a different order. If you (or other people) never ever ever UPDATE or DELETE a table, then on some databases the data might well come out in insertion order for a very very long time; given human nature and the way projects tend to work, relying on that is a sucker's bet, IMHO.
In other words, if you want the "most recent" something, you need to store a timestamp with your data. (With some databases, you might be able to take advantage of some non-standard feature to get "last updates" or "row change timestamps", but I know of no such for Postgres.
While this won't solve your major problem, above, your issue with rs.last is probably occuring because Postgres by default will prefetch your entire ResultSet. Use Statement.setFetchSize() to change that (PreparedStatement inherits the method, of course).

Getting the first row for each group

Hi Everyone,
I have a query which returns a number of rows, all of which are valid. What I need to do is to get the first row for each group and work with those records.
For example ...
client flight startairport destairport stops
A fl123 LGW BKK 2
A fl124 LHR BKK 5
B fl432 LGW XYZ 7
B fl432 MAN ABC 8
.... etc.
I would need to return one row for Client A and one row for Client B (etc.) but find that I can't use the MIN function because it would return the MIN value for each column (i.e. mix up the rows). I also can use the rownum=1 because this would only return one row rather than one row per group (i.e. per client).
I have been investigating and most postings seem to say that it needs a second query to look up the first row for each grouping. This is a solution which would not really be practical because my query is already quite complex and incorporating duplicate subqueries would just make the whole thing much to cumbersome.
So what I really new is a "MIN by group" or a "TOP by group" or a "ROWNUM=1 by group" function.
Can anyone help me with this? I'm sure that there must be a command to handle this.
Regards and any thanks,
Alan Searle
Cologne, Germany

Something like this:
select *
from (
   select table1.*
   row_number() over (partition by col1, col2 order by col3, col4) rn
   from table1
where rn = 1In the "partition by" clause you place what you normally would "group by".
In the "order by" clause you define which will have row_number = 1.
Edit:
PS. The [url http://download.oracle.com/docs/cd/E11882_01/server.112/e17118/functions004.htm#i81407]docs have more examples on using analytical functions ;-)
Edited by: Kim Berg Hansen on Sep 16, 2011 10:46 AM

Getting the first row of a result set

I need to get the first row returned from a select query that looks like this:
SELECT DISTINCT parm1 FROM table1 WHERE parm1 > 10 ORDER BY parm1
Can someone please show me how to do this?
Alex

Because you're only getting one row you don't need to bother with a DISTINCT clause. You'll need to order your data first and then nab the first row from that result set.
SELECT parm1
FROM (SELECT   parm1
            FROM table1
           WHERE parm1 > 10
        ORDER BY parm1)
WHERE ROWNUM <= 1;

Getting the Selected Row from a JTable

hi,
how Can i get the Selected row from a JTable
thanks...

You know that JTable class? Well, you see those methods in it called "getSelectedRow()" and "getSelectedRows()"...?

How can I get the selected rows from two ALV grids at the same time?

I have a program that uses two ALV grids in one dialog screen. I'm using the OO ALV model (SALV* classes).
The user can select any number of rows from each grid. Then, when a toolbar pushbutton is pressed, I'd have to retrieve the selected rows from both grids and start some processing with these rows.
It is no problem to assign event handlers to both grids, and use the CL_SALV_TABLE->GET_SELECTIONS and CL_SALV_SELECTIONS->GET_SELECTED_ROWS methods to find out which rows were marked by the user. Trouble is, this only works when I raise an event in each grid separately, for instance via an own function that I added to the grid's toolbar. So, I can only see the selected rows of the same grid where such an event was raised.
If I try to do this in the PBO of the dialog screen (that contains the two grids), the result of CL_SALV_SELECTIONS->GET_SELECTED_ROWS will be empty, as the program does not recognize the marked entries in the grids. Also, an event for grid1 does not see the selected rows from grid2 either.
As it is right now, I can have an own button in both grid's toolbar, select the rows, click on the extra button in each grid (this will tell me what entries were selected per grid). Then, I'd have to click on a third button (the one in the dialog screen's toolbar), and process the selected rows from both grids.
How can I select the rows, then click on just one button, and process the marked entries from both grids?
Is it somehow possible to raise an event belonging to each grid programmatically, so that then the corresponding CL_SALV_SELECTIONS->GET_SELECTED_ROWS will work?
Thanks.

Hello Tamas ,
If I try to do this in the PBO of the dialog screen (that contains the two grids), the result of CL_SALV_SELECTIONS->GET_SELECTED_ROWS will be empty, as the program does not recognize the marked entries in the grids. Also, an event for grid1 does not see the selected rows from grid2 either.--->
is it possible to have a check box in each grid & get the selected lines in PAI of the screen ?
regards
prabhu

Master Child tables how to get the latest rows from both

Hi,
Need some help with the sql. I have two tables Master & Child. In my Master table I have multiple rows for the same record and in the child table also multiple rows for the same master row how can I get the latest one's from both.
For example Data in my Master table looks like
CONT_ID                  SEQ_NUM        DESCRIPTION
1                         189             Update 2
1                         188             Update 1
1                         187              NewNow in the child table for the same CONT_ID I may have the following rows
CONT_ID                   UPDATED_DATE                                     STATUS
1                        3/16/2010 2:19:01.552700 PM                          P
1                        3/16/2010 12:29:01.552700 PM                         A
1                        3/16/2010 12:29:01.552700 PM                         P
1                        3/16/2010 12:19:01.552700 PM                         NIn my final query how can I get the row with seq_num 189 as it's the latest in Master table and from child table the row with status of P as it's the latest one based on the time. Here is the query i have but it returns the latest row from the child table only and basically repeats the master table rows as opposed to one row that is latest from both:
Thanks

Hi,
You can use the analytic ROW_NUMKBER function to find the latest row for each cont_id in each table:
WITH     got_m_rnum     AS
     SELECT     cont_id,     seq_num,     description
     ,     ROW_NUMBER () OVER ( PARTITION BY cont_id
                               ORDER BY         seq_num     DESC
                       ) AS m_rnum
     FROM    master_table
--     WHERE     ...     -- any filtering goes here
,     got_c_rnum     AS
     SELECT     cont_id, updated_date,     status
     ,     ROW_NUMBER () OVER ( PARTITION BY cont_id
                               ORDER BY         updated_date     DESC
                       ) AS c_rnum
     FROM    child_table
--     WHERE     ...     -- any filtering goes here
SELECT     m.cont_id,     m.seq_num,     m.description
,     c.updated_date,     c.status
FROM     got_m_rnum     m
JOIN     got_c_rnum     c     ON     m.cont_id     = c.cont_id
                    AND     m.m_rnum     = c.c_rnum
                    AND     m.m_rnum     = 1
;If you'd like to post CREATE TABLE and INSERT statements for the sample data, then I could test this.
If there happens to be a tie for the latest row (say, there are only two rows in the child_table with a certain cont_id, and both have exactly the same updated_date), then this query will arbitrarily choose one of them as the latest.

To get the first row

hi all,
i have query like
select container,size,serial
from containers
order by serialin the above query for the same container and size there might be more than one serial.out of that i have to sort it by serial and fetch the first row.
can we fetch with row num, before fetching rownum =1 we should order it first?
Please help me..

So for a given container (say :b1) and size (say :b2), you want to retrieve the row with the smallest serial value?
I think this should work then:
select *
from (select container,size,serial
      from containers
      where container = :b1
        and size = :b2
      order by serial)
where rownum = 1

How to get the last row in a resultset or query

Hi All
Say If I have a complex query which returns a resultset say 15 rows. Now I want to limit the output showing only the last row.
How can we do this

Keep in mind Oracle does not keep "row" order as such. Unlike a graphical type db like Access, Oracle will not always give you back the results in order.
Even if you were to use a sequence, your query is never guaranteed to give back the results in the order you are expecting. You must then give an order by statement to all queries expecting the order.
Your definition of last row too is vague - if it is in fact the greatest amount, use the inline view suggestion. If you simply want to see the last inserted row, consider adding a last_update_date column inserting the sysdate (by a trigger perhaps). This would then allow you to see the last inserted row.
Enjoy!

Getting the selected row from a datatable -- URGENT

Hi,
I am facing the following problem with a datatable. The datatable does not have any Input components like CommandLink, Buttons, Radio Buttons and Checkbox. Even I cannot use the hidden Command Link.
One solution is to use a input hidden variable which can hold the curent row Id. But in this case too, how to get the control in a backing bean method is not clear to me.
Please guide me how to get the data of the selected row in the backing bean.
Thanks in advance......
VJain.

I again explain my problem:
I need to get the Current Selected Row onclick of any row in a Datatable. But the datatable is restricted not to have any CommandLink or Input component so that I can generate the action to go to any method on a backing bean as shown below.
<h:dataTable id="dTable" value="#{Bean.myList}" var="currentRow" >
<h:column id="row1">
<h:outputText value="# currentRow.productNumber}"></h:outputText>
</h:column>
<h:column id="row2">
<h:outputText value="# currentRow.productName}"></h:outputText>
</h:column>
</h:dataTable>
As shown above I cannot use any commandButton or CommandLink to submit the page. All I can do is to generate any onclick function on Table and do something with it. But not sure how to do it.
Now I want the productNumber of the selected row in any method say getCurrentRowId of the Bean.
I hope the problem must be clear now....
Thanks for your quick reply..
VJ

How to get the latest row from my Logical Table Source?

Hi everyone,
I have a SALARY_HISTORY table that holds the Salary Date and the Salary Amount for an employee, as a simple example. In my Business Model, I want to have a Display Folder called "Current Salary" and use the Where Clause restriction to derive the latest salary for each of my employees.
In standard SQL Plus, I used a nested SQL statement, e.g. "where a.SalaryDate = (select max(b.SalaryDate) from SALARY_HISTORY b where b.employeeid = a.employeeid)".
Is there anyway in the "Where Clause" filter of the LTS to derive this type of a query?
I have tried things like "DB".""."SCHEMA"."AL_SALARY_HISTORY"."SalaryDate" = EVALUATE('SELECT_PHYSICAL MAX(SALARY_DATE) FROM "DB".."SCHEMA"."AL_SALARY_HISTORY" WHERE employeeid = %1)', "DB".""."SCHEMA"."AL_SALARY_HISTORY"."employeeid"). And I know I can't use any of the analytic functions in a where clause.
So how do I go about this other than creating a View in the database or creating a function in the database to give me the maximum salary date for my employee?
Thanks
Paul

Hi Paul,
You could achieve this requirement using a sub query. Briefly, the steps are
1. Just create one report with max(salary_date) for each employee.
2. Create another report with SALARY_DATE included.
3. Create a filter (Based on another analysis) on this report, as employee is in(Employee of report in step1) AND SALARY_DATE IS IN(SALARY_DATE of report in step1)(this is the max_salary_date for him)
You could notice that BI Server would send two queries to the backend for this info.
Hope this helps.
Thank you,
Dhar

Help getting the first value from a arraylist

Hi
I have a arraylist, and when i print it out it prints out.
[ben, ben, ben]
[alex, alex]
[matt, matt]
[mum, mum]
[dad]
How can get it to print out so that it will say this?
ben
alex
matt
mum
dad
thanks
nicky

nnickys,
I showed you how to do exactly this only a few days ago.
http://forum.java.sun.com/thread.jsp?forum=31&thread=349885
If you didn't understand how it worked then I would have been more than happy to explain it to you.
Within the code we retreive a String array that contains one of the lines of your ArrayList. (The code loops through returning each one...);
// retrieve each element in turn
String[] thisLine = (String[]) li.next();
You could then loop through this and output each element of that array, like this...
for (int i=0; i<thisLine.length; i++) {
System.out.println(thisLine);
I hope this helps, salvadorEscobar.

How to get the first or last row value from a group using ntile

I want to query and use ntile to divide by data in 4 groups (quartiles). I got this part no problem and it returns the list of rows and the ntile bucket value for each one.
What I want though is to get only the first row from each ntile group (so in effect the max, q3, median, q1 and min values from the whole result). Of course I coud get max, min and median directly using the other functions, but how about the values for q3 and q1?
My query contains this:
NTILE(4) OVER (ORDER BY salary DESC NULLS LAST) as ntile
So I want the highest, lowest, middle, q3 and q1 values for the salaries.
Should I be using NTILE, ROWNUM, PERCENTIL_DIST....?
Any ideas? Thanks in advance.

SQL> select ename,sal,
2 NTILE(4) OVER (ORDER BY sal DESC NULLS LAST) as ntile
3 from emp
4 /
ENAME             SAL      NTILE
KING             5000          1
FORD             3000          1
SCOTT            3000          1
JONES            2975          1
BLAKE            2850          2
CLARK            2450          2
ALLEN            1600          2
TURNER           1500          2
MILLER           1300          3
WARD             1250          3
MARTIN           1250          3
ENAME             SAL      NTILE
ADAMS            1100          4
JAMES             950          4
SMITH             800          4
14 rows selected.
SQL> select ename,
2          sal
3    from (
4           select ename,
5                   sal,
6                   ROW_NUMBER() OVER (PARTITION BY ntile ORDER BY sal DESC NULLS LAST) as rn
7             from (
8                    select ename,
9                            sal,
10                            NTILE(4) OVER (ORDER BY sal DESC NULLS LAST) as ntile
11                      from emp
12                   )
13          )
14    where rn = 1
15 /
ENAME             SAL
KING             5000
BLAKE            2850
MILLER           1300
ADAMS            1100
SQL> SY.

How to get first row from view iterator programatically?

Hi All,
I am using Jdeveloper 11g Release 2.
I want to fetch the first row of a view iterator in a bean. Can any one guide me through this use case.
Any help will be highly appreciated.
Thanks ... Best Regards
Bilal

Use the code snippet as below:
*// 1. Access the binding container*
DCBindingContainer bc = (DCBindingContainer)BindingContext.getCurrent().getCurrentBindingsEntry();
*// 2. Find a named iterator binding*
DCIteratorBinding iter = (DCIteratorBinding)bc.findIteratorBinding("<ITERATOR_NAME>");
*//3. Get the RowSetIterator Object*
RowSetIterator rsi = iter.getRowSetIterator();
*//4. Get the First Row*
Row firstRow = rsi.first();
Thanks,
Navaneeth

Getting the first record

I have a table containing infor about employees promotion details.Problem is that the table was so badly designed that the only way for me to know the first promotion that an employee got in that year was the way it was inserted.Hence below for Manohar ,91 was the first promotion in the year 2001 and
for Sanohar it is 81.
Wondering is there sql query throught which I can get hold of the first record that was inserted.
YEAR____EMPCODE_____NAME_______POSITION
2001______02_________Manohar________91
2001______02_________Manohar________01
2001______02_________Manohar________07
2001______03_________Sasohar________81
2001______03_________Sasohar________84
2001______03_________Sasohar________87

this migth be of help:
SQL> select rowid, year, empcode, name, position
2    from employees;
ROWID              YEAR EM NAME       PO
AAD8PAAAJAAAAzwAAA 2001 02 Manohar    91
AAD8PAAAJAAAAzwAAB 2001 02 Manohar    01
AAD8PAAAJAAAAzwAAC 2001 02 Manohar    07
AAD8PAAAJAAAAzwAAD 2001 03 Sasohar    81
AAD8PAAAJAAAAzwAAE 2001 03 Sasohar    84
AAD8PAAAJAAAAzwAAF 2001 03 Sasohar    87
6 rows selected.
Elapsed: 00:00:00.00
SQL> select emp.year, emp.empcode, emp.name, emp.position,
2         emp.promotion, rowid
3    from (select year, empcode, name, position,
4                 rank() over (partition by empcode order by rowid) promotion
5            from employees) emp
6 /
YEAR EM NAME       PO PROMOTION ROWID
2001 02 Manohar    91          1 AAD8PAAAJAAAAzwAAA
2001 02 Manohar    01          2 AAD8PAAAJAAAAzwAAB
2001 02 Manohar    07          3 AAD8PAAAJAAAAzwAAC
2001 03 Sasohar    81          1 AAD8PAAAJAAAAzwAAD
2001 03 Sasohar    84          2 AAD8PAAAJAAAAzwAAE
2001 03 Sasohar    87          3 AAD8PAAAJAAAAzwAAF
6 rows selected.
Elapsed: 00:00:00.00
SQL> note: you can use the rowid to identify which row has been inserted first. if this is something that you want to get the first row that was inserted.

Getting the first row from a ResultSet??

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