Re: [GENERAL] [NOVICE] How to split a table?

[Obe, Regina]

I would do
 
select * into mynewtable 
from myoldtable ORDER by random() LIMIT 15000
 
where 15000 in this case is *.6
 
If you want to create another table with 40% of the 
remaining data then something like
 
select * into mynewtable2 from myoldtable where 
myoldtable.primarykey NOT IN(select primarykey from 
mynewtable)
]
In this case primarykey you would replace with the 
primary key field of your table.


From: [EMAIL PROTECTED] 
[mailto:[EMAIL PROTECTED] On Behalf Of Felix 
ZhangSent: Tuesday, October 17, 2006 3:39 AMTo: 
pgsql-sql@postgresql.org; pgsql-general@postgresql.org; 
[EMAIL PROTECTED]Subject: [NOVICE] How to split a 
table?

Hi,
 
I want to split a table to 2 small tables. The 1st one contains 60% records 
which are randomly selected from the source table.
How to do it?
 
Regards,
Felix




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Re: [GENERAL] [NOVICE] How to split a table?

[Christoph Frick]

On Tue, Oct 17, 2006 at 03:39:21PM +0800, Felix Zhang wrote:

> I want to split a table to 2 small tables. The 1st one contains 60%
> records which are randomly selected from the source table.  How to do
> it?

i do my A/B-Group splitting usually by &1 the serial of the table.
assuming, that there are no irregularities in the process of creating
your entries, this should give a 50/50 split, which is reuseable for
future things and there never is a intersection of the two groups.

-- 
cu


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