Question

CatID  parID  catName
1      -1        A
2       1        B  
3       2        C
4       3        D

I want to write a query which returns the parent child relationship in string format.

In the above table the catName has parentId -1, which means it has got no parent. B has parentID 1, which means that A is its parent.

So finaly the string is like this

A=>B=>c=>D

This is the way I want to generate a query.

I’ll pass CatID, and it will traverse until it gets a -1.

Answer 1

declare @CatID int;
set @CatID = 4;

with C as
(
  select parID,
         cast(catName as varchar(max)) as catName
  from YourTable
  where CatID = @CatID
  union all
  select T.parID,
         T.catName + '=>' + C.catName
  from YourTable as T
    inner join C
      on T.CatID = C.parID
)
select catName
from C
where parID = -1

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