Обсуждение: Updating a table from another table

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Updating a table from another table

От
Matthew Price
Дата:
Howdy All,

I need to update many records in one table with data from another table that ultimately gets \copy-ed from an outside
source.

customers:
custnum varchar(6),
name text,
canceldate date
...

cancels:
custnum varchar(6),
canceldate date


What is the right way to update the canceldate in the customers table from canceldate in the cancels table?  Is there a
wayto use update to iterate rather than making a mass change?
 

Thanks in advance,
Matthew




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Re: Updating a table from another table

От
Jean-Luc Lachance
Дата:
Try:

UPDATE customers
SET canceldate = cancels.canceldate
FROM cancels
WHERE customers.custnum = cancels.custnum;

You should also have an index on cancels(custnum).

JLL



Matthew Price wrote:
> 
> Howdy All,
> 
> I need to update many records in one table with data from another table that ultimately gets \copy-ed from an outside
source.
> 
> customers:
> custnum varchar(6),
> name text,
> canceldate date
> ...
> 
> cancels:
> custnum varchar(6),
> canceldate date
> 
> What is the right way to update the canceldate in the customers table from canceldate in the cancels table?  Is there
away to use update to iterate rather than making a mass change?
 
> 
> Thanks in advance,
> Matthew
> 
> ________________________________________________________________
> GET INTERNET ACCESS FROM JUNO!
> Juno offers FREE or PREMIUM Internet access for less!
> Join Juno today!  For your FREE software, visit:
> http://dl.www.juno.com/get/web/.
> 
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