Backup and restore column values

I need to do a mass update to a column value. If there are issues I'll nee开发者_如何学Cd to be able to revert the column back to it's previous value. So I'm backup the values to a temporary table.

BTW, I'm using Oracle.

CREATE TABLE tmp_trial_date_backup AS SELECT cust_id, trial_days FROM customer 
WHERE (trial_days = 0 or trial_days = -99) 

Subsequently I'll perform the update.

UPDATE customer SET trial_days = 1 WHERE (trial_days = 0 or trial_days = -99)

My quest is... How can I restore the column values from the tmp table I've created ?do

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In the end I did the following.

UPDATE customer c SET trial_days = (SELECT trial_days from tmp_trial_days_backup 
where tmp_trial_days_backup.cust_id = customer_bond.cust_id)
WHERE EXISTS (SELECT 1 from tmp_trial_days_backup tmp WHERE tmp.cust_id = c.cust_id)

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Following update resets the trial_days from customer on a SQL Server database.

UPDATE  c
SET     trial_days = tmp.trial_days
FROM    customer c
        INNER JOIN tmp_trial_date_backup tmp ON tmp.cust_id = c.cust_id

Perhaps easier might have been to add a column trial_days_backup to the customer table.