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Archives of the TeradataForum
Message Posted: Thu, 23 Apr 2015 @ 12:59:08 GMT
| Subj: | | Re: Impact of using NOT IN vs AND condition |
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| From: | | Dieter Noeth |
Anomy.Anom wrote:
| | I ran the explain on both the queries and found that the plans were exactly the same. I believe that since its a non-equality condition
then the query will result in a FTS anyway (for both instances).. Why is it that it is recommended that NOT IN clauses be avoided in
queries? | |
NOT IN with values is ok, only "NOT IN (SELECT...)" subqueries should be avoided, because then NULLs become an issue due to three-valued logic
and the plan will be quite ugly when NULLable columns are involved. Then better rewrite to NOT EXISTS instead.
Dieter
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