0
Follow
0
View

Oracle 19: Why IN gets converted to Exist in explain plan and any suggestions around it

eg2699610 注册会员
2023-01-25 17:33

IN clause retrieves all records which match with the given set of values. It acts as multiple OR conditions. IN clause scans all rows fetched from the inner query. But, EXISTS is a Boolean operator that returns either True or False. Its used in combination to a sub-query. If the subquery returns any row, it returns True else False. If the result of data large inside the IN clause, then not recommended using IN. For getting high performance most time uses EXISTS vs IN. For that Oracle and PostgreSQL converts your IN to EXISTS

About the Author

Question Info

Publish Time
2023-01-25 17:33
Update Time
2023-01-25 17:33