Syntax

Inner:

1. <TableExpression> [INNER] JOIN <TableExpression> ON <BooleanExpression>

2. Implicit Syntax: select * a, b where a.id = b.id;

Left Outer:

1. <TableExpression> LEFT [OUTER] JOIN <TableExpression> ON <BooleanExpression>

2. Using + operator. select * from table a, b where a.id+ = b.id (Oracle)

3. Using * operator. select * from table a, b where a.id *= b.id

Full Outer Join

1. <TableExpression> FULL [OUTER] JOIN <TableExpression> ON <BooleanExpression>

Note: Oracle recommends to use OUTER JOIN SYNTAX than to use operator (+).

References:

1. http://docs.oracle.com/cd/B19306_01/server.102/b14200/queries006.htm

2. http://docs.oracle.com/javadb/10.6.2.1/ref/rrefsqlj29840.html#rrefsqlj29840