INNER and LEFT OUTER join help

 SELECT * FROM TableA 
       INNER JOIN TableB ON TableB.id = TableA.id
       LEFT JOIN TABLEC ON TABLEC.id = TABLEB.id

      

        
        
        
      

    

I don't know what columns you are trying to use, but it is just that simple

Edit: Looking at your edit, it seems like you are confused about what Joins is actually doing. In the above example, you will get the following results.

Columns -> You will get all columns for TableA, TableB and TableC

Rows-> You will start with all rows from Table A. Then you will delete all rows from Table A that do not have a corresponding "id" in Table B. (You will have duplicates if it is not a 1: 1 ratio between TableA and TableB) ...

Now, if you take the results from the top, you will be matching any records from Table C that match the TableB.id column. Any rows from above that do not have a matching TableC record will get null for all columns from TableC in the results.

ADVICE. I'm sure only part of this makes sense to you, but my advice is that you start writing some queries, predict the results, and then see if your predictions are correct to figure out what you are doing.

Select * from ((((TableA a inner join TableB b on a.id = b.id) 
                left outer join TableC c on b.id = c.id)
                full outer join TableD d on c.id = d.id)
                right outer join TableE e on e.id = d.id)
                /* etc, etc... */

      

        
        
        
      

    

You can loose the parentheses if you like.

try it.

SELECT *
  FROM TableA              a 
       INNER JOIN TableB   b ON a.id=b.id
       LEFT OUTER JOIN (SELECT *
                            FROM TableC            c
                                INNER JOIN TableD  d on c.id=d.id
                       ) dt on b.id=dt.id

      

        
        
        
      

    

Assuming I understand your question, I think this is what you are asking for:

SELECT * 
FROM TableA INNER JOIN TableB on TableA.JoinColumn = TableB.JoinColumn
LEFT OUTER JOIN TableC on TableB.JoinColum = TableC.JoinColumn
INNER JOIN TableD on TableC.JoinColumn = TableD.JoinColumn

      

        
        
        
      

    

Note that the JoinColumn used to join A and B does not have to be the same column as the one used to join B and C, and so on for C and D.

You haven't specified join conditions or explained how tables should be linked, so it's not clear how this can be simplified.

SELECT a.a_id, b1.b_id b1_id, b2_id, bc.c_id
FROM TableA a JOIN TableB b1 on a.b_id = b1.b_id
LEFT JOIN (SELECT c.c_id, b2.b_id b2_id
    FROM TableC c JOIN TableB b2 ON c.b_id = b2.b_id
  ) bc ON bc.c_id = a.c_id;

      

        
        
        
      

    

Looking at your last edit, you can do something like:

SELECT <columns>
FROM (SELECT <columns> FROM TableA JOIN TableB ON <A-B join conditions>)
           LEFT JOIN
           (SELECT <columns> FROM TableC JOIN TableD ON <C-D join conditions>)
           ON <AB-CD join conditions>

      

        
        
        
      

    

Although you really don't need internal projections and can do:

SELECT <columns>
FROM (TableA a JOIN TableB b ON <A-B join conditions>)
           LEFT JOIN
           (TableC c JOIN TableD d ON <C-D join conditions>)
           ON <AB-CD join conditions>

      

        
        
        
      

    

If AB-CD join conditions are written in terms of columns a, b, c, d, etc. directly.

Since you are using Sql Server, why not create views to help you? Filling everything in a giant Sql statement can get hard to read. An approximate view might look like this:

create view AandB
as
select *
from A
inner join B on B.aid = A.aid

      

        
        
        
      

    

And the same goes for CandD. Then you can get an optional connection with plain Sql:

select *
from AndB
left outer join CandD on AndB.cid = CandD.cid

      

        
        
        
      

    

If you are interested in strings from both sets, you can do a full join:

select *
from AndB
full outer join CandD on AndB.cid = CandD.cid