CODEWITHSUNDEEP
mysqlsqldatabaserecursion
Dhaval
Dhaval

Reputation: 978

How can I make recursive query in SQL?

I have tow tables like

users

id | name
_______________
1  | one
2  | two
3  | three
4  | four
5  | five
6  | six

employees

id | userId | reportedTo
_________________________
1  | 1      |   null
2  | 2      |   1
3  | 3      |   2
4  | 4      |   3
5  | 5      |   4
6  | 6      |   5

I need something like

if I run query for some user then it will return all the record which reportedTo is this user and other users which reportedTo is reportedTo this user

Like:

if I run this query for user 1 then it will return all the record accept userId 1 from employees

id | userId | reportedTo
    _________________________
    2  | 2      |   1
    3  | 3      |   2
    4  | 4      |   3
    5  | 5      |   4
    6  | 6      |   5

if I run query for userId 4 then it will return recornds with userId 5 and 6 from employee table

id | userId | reportedTo
    _________________________
    5  | 5      |   4
    6  | 6      |   5

can anyone help me with this.

Thanks in advance

Upvotes: 2

Views: 199

Answers (1)

Ajax1234
Ajax1234

Reputation: 71451

You can use a recursive CTE:

with recursive cte(i, u, r) as (
   select * from employees where reportedTo = 1
   union all
   select e.* from cte c join employees e on c.u = e.reportedTo
)
select c.i id, c.u userId, c.r reportedTo from cte c;

Output:

id userId reportedTo
2 2 1
3 3 2
4 4 3
5 5 4
6 6 5

See demo

Upvotes: 2

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