By the way, level is reserved, can’t use it in SQL unless you quote it.

 SELECT emp.name, emp.passport, edu."level"
   FROM emp, edu
  WHERE emp.passport = edu.passport;

Or using ANSI SQL:

 SELECT emp.name, emp.passport, edu."level"
   FROM emp inner join edu on emp.passport = edu.passport;

emp ( name, passport PK)
with 3 DATA :
(’FORD’,'900000′ ), (’CHANG’,'989999′),(’CRISS;,’877777′)
table edu(’passport’ ,’level’,'result’)
with 6 DATA :
(’900000′ ,’DIPLOMA’,'3.4′)
(’900000′ ,’DEGREE’,'3.0′)
(’900000′ ,’MASTER’,'4.0′)
(’989999′ ,’HIGHSCHOOL’,'2.0′)
(’989999′ ,’DEGREE’,'3.0′)
(’877777′ ,’HIGHSCHOOL’,'2.5′)

RESULT SHOULD LIKE THIS

NAME PASSPORT LEVEL
—————————————————
FORD 900000 DIPLOMA DEGREE ASTER
CHANG 989999 HIGHSCHOOL DEGREE
CRISS 877777 HIGHSCHOOL

is it posibble to do the SQL join ?
thanks so much

Another Question
I have 2 table :
T1 have a1,b1,c1 fields
T2 have x2,x3,x4, a1 as FK from T1. These two table has a one to many relationship. How I want to display the two table as one record?
exp result :
a1,b1,c1,x2,x3,x4
a1,b1,c1,x3,x4
a1,b1,x2,x3,x4

thanks

an INNER join is one that isn’t an OUTER join. Or to be more specific: for a row to occur in the result relation, its component pieces must be present in BOTH of the source relations. An OUTER join, in contrast, can supply null values for “missing” rows (in either or both of the source relations, depending on whether this is a LEFT, RIGHT or FULL outer join).

an EQUI join is a special case join in which the predicates are based on equality conditions eg
WHERE EMP.DEPTNO = DEPT.DEPTNO. Foreign key joins are examples of equijoins.

EQUI joins can be INNER or OUTER joins:
SELECT EMP.NAME, … , DEPT.DNAME
FROM EMP, DEPT
WHERE EMP.DEPTNO = DEPT.DEPTNO — inner join, equi join

or
WHERE EMP.DEPTNO = DEPT.DEPTNO (+) — outer join, equi join

In spite of being an old Oracle hacker, I actually prefer to use ANSI syntax as it is (I think) much more readable/maintainable, eg:

SELECT EMP.NAME, … , DEPT.DNAME
FROM EMP
LEFT JOIN DEPT ON EMP.DEPTNO = DEPT.DEPTNO — outer join, equi join

HTH

Nigel

SELECT emp.emp_name,
dept.dept_name
FROM emp INNER JOIN dept
ON emp.dept_id = dept.dept_id
INNER JOIN addresses
ON emp.address_id = addresses.address_id