Who knows, the query and sort the where clause for the Oracle performance comparison?

CodePudding user response:

Specific??

CodePudding user response:

Say a bit more detailed;

CodePudding user response:

ORACLE order should be written in the WHERE clause for now already not important, the CBO will automatically choose the best execution plan

CodePudding user response:

Order by using the index of the condition is very strict, only to meet the following conditions can be used to index:
1. The order by the column must contain the same index and index sequence and sort order is consistent,
2. Cannot have a null value column
So the performance of the sort often is not high, it is suggested that as far as possible to avoid the order by