Oracle left and right connections

In Oracle, the left and right join statements in SQL Server are saved, and they are represented by a "(+.
In the following experiment, query 1 and query 2 are equivalent, and query 3 and query 4 are equivalent.

Query 1:
Select first_name, department_name, EMP. department_id from EMP, parameters Dept
Where EMP. department_id (+) = Dept. department_id;

122 rows selected.

Query 2:
Select first_name, department_name, EMP. department_id from orders ments dept left join EMP
On EMP. department_id = Dept. department_id;

122 rows selected.

 

 

Query 3:
Select first_name, department_name, EMP. department_id from EMP, parameters Dept
Where EMP. department_id = Dept. department_id (+ );

107 rows selected.

Query 4:
Select first_name, department_name, EMP. department_id from EMP left join partitions Dept
On EMP. department_id = Dept. department_id;

107 rows selected.

 

Summary:

1. Where is the (+) side, all records on the other side are returned.

2. (+) is placed on one side that contains null values. It cannot be used on both sides at the same time.

 

 

The supplementary inline method uses the Using Keyword:

Select first_name, department_name, department_id from EMP join orders ments dept using (department_id );

Note: The fields in using cannot contain aliases, and the fields in using in select_list cannot contain aliases. See the following two examples:

Select first_name, department_name, EMP. department_id from EMP join conditions dept using (EMP. department_id );
Using (EMP. department_id)
*
Error at line 2:
ORA-01748: only simple column names allowed here

Select first_name, department_name, EMP. department_id from EMP join conditions dept using (department_id );
Select first_name, department_name, EMP. department_id from EMP join statements Dept
*
Error at line 1:
ORA-25154: column part of using clause cannot have qualifier

 

Join using, which is equivalent to inner join

Select EMP. first_name, Dept. department_name, EMP. department_id from EMP join orders ments Dept
On EMP. department_id = Dept. department_id;