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Topic: What is the difference between UNION ALL Statement and UNION
Sachin Jain
29 Oct 2010 at 11:50 PM
What is the difference between UNION ALL Statement and UNION.
Re: What is the difference between UNION ALL Statement and UNION
Gaurav
01 Nov 2010 at 12:03 AM

UNION - this command will allow you to join multiple datasets into one dataset and will remove any duplicates that exist. Basically it is performing a DISTINCT operation across all columns in the result set.
UNION ALL - this command again allows you to join multiple datasets into one dataset, but it does not remove any duplicate rows.  Because this does not remove duplicate rows this process is faster, but if you don't want duplicate records you will need to use the UNION operator instead.

Total Replies: 1
 
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