Table Joins

Question

Hi,

I have the table and joins below which is working as I would expect. However, I need to join in another table mort.dbo.staff but the problem I have is the field I need to join on doesn't exist within the mort.dbo.new_cust . However, this does exist on a table that I am using already mort.dbo.ex_custr.

Is there anyway that within this join below, I can join the new table mort.dbo.staff as d left join mort.dbo.ex_custr as b on d.staff_id = b.staff_id?

from mort.dbo.new_cust as a

inner join mort.dbo.ex_custr as b
on a.cust_no = b.cust_no

inner join mort.dbo.platform as c
on a.mort_no = c.mort_no)

Answer 1

Is there anyway that within this join below, I can join the new table mort.dbo.staff as d left join mort.dbo.ex_custr as b on d.staff_id = b.staff_id?

May or may not; we don't know your database design.

Please post table design as DDL, some sample data as DML statement and the expected result.

Answer 2

Hi @Bone_12 ，

Yes, you can:

from new_cust as a  
inner join ex_custr as b  
on a.cust_no = b.cust_no  
inner join platform as c  
on a.mort_no = c.mort_no  
left join staff as d  
on d.staff_id = b.staff_id  

Please refer to the following example.The connected field in the book table does not exist in the Student table, but we can still connect the book table and the Student table through the borrow table:

SELECT * FROM Student  
SELECT * FROM book  
SELECT * FROM borrow  

Output:

SELECT * FROM Student s  
JOIN borrow b  
ON s.stuID=b.BstuID  
JOIN book bo  
ON b.BID=bo.BID  

Output:

If you have any question, please feel free to let me know.

Regards
Echo

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