Question

Here is the DB available.

create table tab1 (
  masterid integer(2) primary key,
  name varchar(22),
  l2 integer(2)
);

insert into tab1 values(1,'g-1',50);
insert into tab1 values(2,'g-1',50);
insert into tab1 values(3,'g-1',50);
insert into tab1 values(50,'grup1',-1);
insert into tab1 values(5,'g-1',50);
insert into tab1 values(60,'grup2',-1);
insert into tab1 values(7,'g-2',60);
insert into tab1 values(8,'g-2',60);

Also available on: http://sqlfiddle.com/#!2/b7fe9/1

Result should be groupwise. For example, Row 50,grup1,-1 is having 50 which will work as primary key and whichever row has that masterID( herein case 50) in l2 column , that should be retrieved.So Basically so I want following output.

MasterId    Name    l2  
   50       grup1   -1
   1        g-11    50
   2        g-12    50
   3        g-13    50
   5        g-14    50
   60       grup2   -1
   7        g-21    60
   8        g-22    60

Note that All the group will have -1 value in L2 column.
I have tried many things but I am confused this output can be achieved or not.I will appreciate your help. Thank you.

Answer 1

Try this query:

SELECT *
FROM tab1
-- Order records by "master id groups", first
ORDER BY CASE WHEN l2 = -1 THEN Masterid ELSE l2 END,
-- Within a "master id group", get the master first and then its children
         CASE WHEN l2 = -1 THEN 0        ELSE 1 END

Optionally, you can amend more expressions to the ORDER BY clause, to order “siblings”