RE: Breaking down values in a large table

From: Khedr, Waleed <Waleed.Khedr_at_FMR.COM>
Date: Tue, 11 Feb 2003 14:54:08 -0800
Message-ID: <F001.0054A292.20030211145408@fatcity.com>

I hope this helps:

---

drop table test_bal ;

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• create a sample table

  ---

  create table test_bal( my_pk number);

  ---

• Insert sample data

  ---

  begin for i in 100..21000 loop insert into test_bal values (i); end loop; end;

  ---

  ---

  select b.rows_cnt as table_rows_cnt, c.mrownum as acc_rows_cnt, c.my_pk as bucket_end_inclusive, ceil(c.mrownum * 4/ b.rows_cnt) as bucket_id from (select a.*,rownum mrownum from (select my_pk from test_bal order by 1) a) c, (select count(*) rows_cnt from test_bal) b where ceil((c.mrownum + 1)* 4/ b.rows_cnt) > ceil( c.mrownum * 4/ b.rows_cnt);

  ---

  ---

Regards,

Waleed

-----Original Message-----
Sent: Tuesday, February 11, 2003 9:19 AM To: Multiple recipients of list ORACLE-L

Listers,
I have a table of 125M rows (not partitioned) which I am exporting. I want to break the export into 4 dmp files using the query command on the pk column.  

I am looking at how the best way of finding the values of the PK (number) which are at 25%, 50% and 75% ish for the table so that I can get 4 evenly sized exports  

My query line in the parameter file will be along the lines of where

1)       log_no < xx
2)       log_no >= xx and < yy
3)       log_no >= yy and < zz
4)       log_no >= zz
 

I am thinking of a sql something like the following  

Select /*+ index ffs(table_name index_name) */ Log_no , floor(log_no / 4), count(*)
>From table_name group by floor(log_no / 4), log_no
 

Version is 8.1.7.1  

Can anybody help please  

Thanks  

John    

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Author: Khedr, Waleed
  INET: Waleed.Khedr_at_FMR.COM

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Received on Tue Feb 11 2003 - 16:54:08 CST