ORACLE-008: classification statistics, oracle008 Classification

ORACLE-008: classification statistics, oracle008 Classification

Classification statistics are usually used to count the number of items or the number of items under a certain item.

Simple, such as tab_test

Tab_test record

Id	Co	Name	Job
1	IBM	JACK	PM
2	Google	TOM	PM
3	IBM	JIM	PM

To calculate this result:

Co: number of people.

The SQL statement is as follows:

Select distinct t. co, count (t. name) from tab_test tgroup by t. co;

Result

Co NAMEIBM 2 Google 1

Tab_test can also be a subquery.

In this case, you can make a statistical query.