oracle not exists

"NOT EXISTS" is a keyword used in Oracle SQL to check the non-existence of rows that satisfy certain criteria in a subquery. It is commonly used in combination with the "SELECT" statement to filter out rows based on conditions. When using "NOT EXISTS," the subquery is evaluated, and if no rows are returned, the condition evaluates to true.

Here's an example to illustrate the usage of "NOT EXISTS":

SELECT column1, column2, ...
FROM table1
WHERE NOT EXISTS (
    SELECT *
    FROM table2
    WHERE condition
);

In this example, the query retrieves records from "table1" where there is no matching record in "table2" that satisfies the specified condition.

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