Thoroughly understand Oracle's left and right outer joins (data speaking) ____oracle

Employees table:

Department Table:

Select E.last_name,e.department_id,d.department_name

From Employees E

LEFT OUTER JOIN Departments D

On (e.department_id = d.department_id);

Select E.last_name, D.department_name

From Employees e, departments D

where e.department_id = d.department_id (+) left outer join

The result is a record of all employees and corresponding departments, including employee records with no corresponding department number department_id.

Select E.last_name,e.department_id,d.department_name

From Employees E

Right OUTER JOIN Departments D

On (e.department_id = d.department_id);

Select E.last_name, D.department_id,d.department_name

From Employees e, departments D

where e.department_id (+) = d.department_id; right outer join

The results are: Records of all employees and corresponding departments, including departmental records without any employees.

Summarize:

Table A right outer join B table

The result is: all B-Table records, and matching A-table records, table A does not match the display null

A (+) =b

A table left OUTER join B

A=b (+)

The result is: All Table A records, and the matching B table records, B table does not match the display null

Classic Summary:

The table with + number does not show all, the table opposite shows all.

formula:

right outer join + on left

LEFT OUTER join + on right

There are + not fully explicit

No + is fully explicit