left outer join returning multiple records

Question

The below query is returning duplicate/multiple records. Is there a way the second left join performed on distinct IDs of SW.MTableId.

SELECT SW.* from
(SELECT * FROM Stable SD,MTable MT WHERE SD.ID=1234 AND SD.ID=MT.Stable_ID) SW  
LEFT OUTER JOIN TTable TD ON (TD.MTable_ID=SW.MTableId AND TD.STATUS='ACTIVE') 
LEFT OUTER JOIN PTable PT ON (PT.MTable_ID=SW.MTableId AND PT.TTable_ID IS NULL) 
enter code here

Duplicate rows:

SW.MTableId TD.MTable_ID  PT.MTable_ID 
71878        67048         849230
71878        67046         849230
71878        67047         849230
71878        67039         849230
71878        67038         849230
71878        67045         849230
71878        67037         849230

http://sqlfiddle.com/#!9/5a127b/2 Have created a fiddle with complete table definitions, the requirement is we need a query to get the primary key columns from each table.

Stable can be direct parent of Ftable, Ttable, Etable, Rtable.
Ftable can be direct parent of Ttable, Etable only.
Ttable can be direct parent of Etable, Rtable.
Etable can be direct parent of Rtable.

#Expected Result

Sid  Fid  Tid  Eid  Rid
2    12   103  203  303
2    12   103  203  304
1    null 101  null 302 
3    null null null 301
1    10   null 202  null
1    null null 201  null  
1    null 102  null null
1    11   null null

Stable
sid, sname
1,   'S1'
2,   's2'
3,   's3'

Ftable
fid, fname, sid
10,  'f1',  1
11,  'f2',  1
12,  'f3',  2

Ttable
tid, tname, fid,  sid
101, 't1',  null, 1
102, 't2',  null, 1
103, 't3',  12,   2

Etable
eid, ename, tid , fid, sid
201, 'e1',  null, null, 1
202, 'e2',  null, 10,   1
203, 'e3',  103,  12,   2

Rtable 
(rid, rname eid  tid  sid)
(301, 'r1'  null null 3) 
(302, 'r2'  null 101  1)
(304, 'r4'  203, 103  2)
(303, 'r3'  203, 103  2)

Answer 1

• You want all rows from rtable and all rows from etable.
• You want those rows from ttable that don't have a match in these previous two tables.
• You want those rows from ftable that don't have a match in these previous three tables.
• You want those rows from stable that don't have a match in these previous four tables.

And you consider null a value, ie you consider null = null a match.

Here is the query doing this step by step.

select sid, null as fid, tid, eid, rid from rtable
union all
select sid, fid, tid, eid, null as rid from etable
union all
select sid, fid, tid, null as eid, null as rid from ttable
  where (sid, coalesce(fid, -1), coalesce(tid, -1)) not in 
    (select sid, coalesce(fid, -1), coalesce(tid, -1) from etable)
  and (sid, coalesce(fid, -1), coalesce(tid, -1)) not in 
    (select sid, -1, coalesce(tid, -1) from rtable)
union all
select sid, fid, null as tid, null as eid, null as rid from ftable
  where (sid, coalesce(fid, -1)) not in
    (select sid, coalesce(fid, -1) from ttable)
  and (sid, coalesce(fid, -1)) not in
    (select sid, coalesce(fid, -1) from etable)
  and (sid, coalesce(fid, -1)) not in
    (select sid, -1 from rtable)
union all
select sid, null as fid, null as tid, null as eid, null as rid from stable
  where sid not in (select sid from ftable)
  and sid not in (select sid from ttable)
  and sid not in (select sid from etable)
  and sid not in (select sid from rtable)
order by sid, fid, tid, eid, rid;

The result is almost the one you have requested. Only, you merge rows of rtable and etable for sid 2 and I don't know why. Well, if this is what you need, you can probably alter my query accordingly.

Demo: http://sqlfiddle.com/#!9/ae1a69/1