PostgreSQL SQL - Query for block updates

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Author

Query for block updates

Amit Shah

2006-12-04, 12:14 am

Hi,

If this question doesn't belong to this mailing list, please pardon.

I have a table with a few hundred million rows, and I need to write a query
that does something like follows --

Change all the values of a column to null where the value cannot be casted to
numeric(20,4)

I have it as varchar, and I need to convert it to numeric(20,4).

I am using this query - alter table optiondata ALTER volume TYPE numeric(20,4)
using cast(volume as numeric(20,4)); then wait for DB to complain, and then
update that value to null, and just keep doing this till all garbadge is
removed :-(

Thanks,
Amit

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