Hi friends
I have a small query on joins

For Example I have
EMP_ID in TABLE A
EMP_NAME in TABLE B
EMP_DESIGNATION in TABLE C
EMP_SALARY in TABLE D

I would like to retreive data from 4 tables using a JOIN command
Do I need to give more than 1 JOIN in the query?
Please give me the query to do this...

Waiting for your replies

Thanks in Advance

Dinesh






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Yes you need 1 join statement for each table except 1 you want to add
to the query. So for your example

SELECT e.id, n.name, d.designation, s.salary
FROM emp_id e
JOIN emp_name n ON e.id = n.empId
JOIN emp_designation d ON e.id = d.empId
JOIN emp_salary s ON e.id = s.empId
WHERE s.salary > 1000
ORDER BY n.name

I have shown all tables linked to your table emp_id but you can join
tables in different combinations to suit as in

SELECT e.id, n.name, d.designation, s.salary
FROM emp_id e
JOIN emp_name n ON e.id = n.empId
JOIN emp_designation d ON e.id = d.empId
JOIN emp_salary s ON d.id = s.designationId
WHERE s.salary > 1000
ORDER BY n.name

Note I changd the join condition on the emp_salary table.

This is a basic example. The join statement has a lot of variations
to allow for different logic in joins. You need to get a decent SQL
manual to see the possibilities.


Hope this helps

Duncan