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SQL Server version of this recursive query example to traverse a tree depth-first http://jakub.fedyczak.net/post/postgresql-with-recursive-tree-traversing-example/
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declare @empl table(name nvarchar(max) null, boss nvarchar(max) null); | |
insert into @empl values ('Paul',null); | |
insert into @empl values ('Luke','Paul'); | |
insert into @empl values ('Kate','Paul'); | |
insert into @empl values ('Marge','Kate'); | |
insert into @empl values ('Edith','Kate'); | |
insert into @empl values ('Pam','Kate'); | |
insert into @empl values ('Carol','Luke'); | |
insert into @empl values ('John','Luke'); | |
insert into @empl values ('Jack','Carol'); | |
insert into @empl values ('Alex','Carol'); | |
with t(level,path,boss,name) as ( | |
select 0,name,boss,name from @empl where boss is null | |
union all | |
select | |
level + 1, | |
path + ' > ' + e.name, | |
e.boss, e.name | |
from | |
@empl e | |
inner join t on e.boss = t.name | |
) select * from t order by path; |
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level path boss name | |
----------- -------------------------------- -------- ------ | |
0 Paul NULL Paul | |
1 Paul > Kate Paul Kate | |
2 Paul > Kate > Edith Kate Edith | |
2 Paul > Kate > Marge Kate Marge | |
2 Paul > Kate > Pam Kate Pam | |
1 Paul > Luke Paul Luke | |
2 Paul > Luke > Carol Luke Carol | |
3 Paul > Luke > Carol > Alex Carol Alex | |
3 Paul > Luke > Carol > Jack Carol Jack | |
2 Paul > Luke > John Luke John |
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Nice. ... Working fine ..