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create table tbl
(
ItemID int,
ParentID int,
TemplateID int
)
insert into tbl values
(1001, NULL, 86),
(1002, 86, 41),
(1003, 43, 44),
(1004, NULL, 43),
(1005, 44, 73);
5 rows affected
UPDATE t1
SET ParentID = t2.ItemID
FROM tbl t1
INNER JOIN tbl t2 ON t1.ParentID = t2.TemplateID
3 rows affected
SELECT *
FROM tbl
| ItemID | ParentID | TemplateID |
|---|---|---|
| 1001 | null | 86 |
| 1002 | 1001 | 41 |
| 1003 | 1004 | 44 |
| 1004 | null | 43 |
| 1005 | 1003 | 73 |