where not exists sql oracle?

Does not exist in Oracle?
Introduction to the Oracle NOT EXISTS operator
SELECT * FROM table_name WHERE NOT EXISTS (subquery); The NOT EXISTS operator returns true if the subquery returns no row. Otherwise, it returns false. Note that the NOT EXISTS operator returns false if the subquery returns any rows with a NULL value.
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How do you avoid not exists in SQL?
Make sure you are searching on indexed columns, with no manipulation of the data within those columns (like substring etc.) Try to replace the NOT EXISTS with a left outer join, it sometimes performs better in large data sets. Pay attention to the other answer regarding indexing. Feb 17, 2009
Full answer in: stackoverflow.com
Where not exists in SQL?
The SQL NOT EXISTS Operator will act quite opposite to EXISTS Operator. It is used to restrict the number of rows returned by the SELECT Statement. The NOT EXISTS in SQL Server will check the Subquery for rows existence, and if there are no rows then it will return TRUE, otherwise FALSE.
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Where not in VS where not exists?
The most important thing to note about NOT EXISTS and NOT IN is that, unlike EXISTS and IN, they are not equivalent in all cases. Specifically, when NULLs are involved they will return different results. To be totally specific, when the subquery returns even one null, NOT IN will not match any rows. Feb 18, 2010
Full answer in: www.sqlservercentral.com
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