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Question regarding DB2 unload

 
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vijay
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Joined: 09 May 2003
Posts: 131
Topics: 64

PostPosted: Thu Jan 27, 2022 9:58 am    Post subject: Question regarding DB2 unload Reply with quote

Hi,
I've to selectively unload data for around 50k accounts from a huge DB2 table. I have the 50k accounts in another DB2 table as well as flat file
Which is a recommended approach to do this

- SQL join between two tables
- Unload the big table to a flat file and do a SORT joinkeys between the two flat files

Thanks,
Vijay
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kolusu
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Joined: 26 Nov 2002
Posts: 12354
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Location: San Jose

PostPosted: Thu Jan 27, 2022 10:20 am    Post subject: Reply with quote

vijay,

Do you indexes on the keys to be matched for both tables? If you have it then a SQL JOIN on both tables might be good.

If you do NOT have indexes defined, then you are better off unloading both tables to flat files and then run Joinkeys

While unloading make sure you ONLY unload the relevant fields necessary.
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vijay
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Joined: 09 May 2003
Posts: 131
Topics: 64

PostPosted: Thu Jan 27, 2022 10:28 am    Post subject: Reply with quote

Thank you Kolusu. Majority of the files are using Indexes. I will try both and see the results on one file

Vijay
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