How to calculate the number of immediate children for each node in an adjacency list

Posted by Travis on Stack Overflow See other posts from Stack Overflow or by Travis
Published on 2010-06-15T03:10:06Z Indexed on 2010/06/15 3:12 UTC
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Filed under:

mysql

|

select

|

mysql-query

|

adjacency-list

I have hierarchical data that I represent using the adjacency list model.

TABLE
    ID
    parentID
    title

I am wondering, what is the simplest way to SELECT the number of immediate children for each node? If possible, I'd like to do this in a single select, yielding a resultset like so...

RESULTS...
ID     title     childCount
1      test1     10
2      test2     2
3      test3     0
etc...

Thanks for your advice!

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