Oracle-L: RE: Breaking down values in a large table

From: <John.Hallas_at_vodafone.co.uk>
Date: Wed, 12 Feb 2003 04:28:38 -0800
Message-ID: <F001.0054A786.20030212042838@fatcity.com>

Thanks Waleed, that is exactly what I wanted. And thanks to all the others who responded

John

-----Original Message-----
Sent: 11 February 2003 22:54
To: Multiple recipients of list ORACLE-L

I hope this helps:

drop table test_bal ;

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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Author: <John.Hallas_at_vodafone.co.uk
INET: John.Hallas_at_vodafone.co.uk

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