I d like (using cte) to count children in table in that way to have at parent level number of all children including theirs children . Is there any sample available?
Hierarchical data - SQL CTE counting childs recursion
De openkb
Sommaire |
Questions
Answers
CREATE TABLE t_parent (id INT NOT NULL PRIMARY KEY, parentID INT NOT NULL) INSERT INTO t_parent VALUES (1, 0) INSERT INTO t_parent VALUES (2, 1) INSERT INTO t_parent VALUES (3, 1) INSERT INTO t_parent VALUES (4, 2) INSERT INTO t_parent VALUES (5, 1) INSERT INTO t_parent VALUES (6, 5) INSERT INTO t_parent VALUES (7, 5); WITH q AS ( SELECT id, parentId FROM t_parent UNION ALL SELECT p.id, p.parentID FROM q JOIN t_parent p ON p.id = q.parentID ) SELECT id, COUNT(*) FROM q GROUP BY id
Source
License : cc by-sa 3.0
http://stackoverflow.com/questions/2191847/sql-cte-counting-childs-recursion