Multi-field connection between oracle tables

The problem of multi-field connection between oracle tables is as follows:

SELECT * FROM table1 a, table2 B, WHERE a.1 = B .1 AND a.2 = B .2 AND a.3 = B .3 ----------

 

In the initial stage, Table a contains the three fields in Table B that are empty and want to join B with the three fields in table.

Method 1: select * from table1 left outer join table2on a.1 = B .1 and a.2 = B .2 and a.3 = B .3 Method 2: <! -- StartFragment --> SELECT. * FROM table1 a, table2 B, WHERE a.1 = B .1 (+) AND a.2 = B .2 (+) AND a.3 = B .3 (+) method 3: <! -- StartFragment --> a.1 | a.2 | a.3 as the primary key

 

B also handles the same, and then connects to the external

SELECT. * FROM (select a.1 | a.2 | a.3 al from table1) a, (select B .1 | B .2 | B .3 bl from table2) B, WHERE. al = B. bl (+)