Oracle Query optimization

The conditions in the WHERE clause in the execution order of Oracle are always precedence over other conditions, and the higher the right, the higher the precedence, including the group BY and ORDER BY clauses.

According to the order of execution, we can summarize many laws that can optimize the query:

1, will be able to filter out the minimum entries of the conditions at the far right of the Where condition

2. The difference between not and not exist is not exist can be judged as NULL, not in will error but execution efficiency is greater than not exist.

3. Prioritize the criteria fields in the WHERE clause to optimize query efficiency for large data volumes

Oracle Query optimization