Oracle performance optimization operation 4: Remove & quot; IN & quot;, & quot; OR & quot; whenever possible. oracle Performance Optimization

Oracle performance optimization operation 4: Remove "IN", "OR" whenever possible, oracle Performance Optimization

The Where clause containing "IN" and "OR" usually uses a worksheet to invalidate the index;

If a large number of duplicate values are not generated, consider splitting the sub-statement. The split sub-statement should contain the index.

Example:

Select count (*) from stuff where id_no in ('0', '1'); -- (23 seconds)

You can consider separating the or clause:

Select count (*) from stuff where id_no = '0'; select count (*) from stuff where id_no = '1 ';

Then, let's make a simple addition. The query speed is faster than that of the original SQL statement.