x
WITH cteCountDownlines AS
( --=== Count each occurrence of EmployeeID in the sort path
SELECT EmployeeID = CAST(SUBSTRING(h.SortPath,t.N,4) AS INT),
NodeCount = COUNT(*) --Includes current node
FROM dbo.Hierarchy h,
dbo.HTally t
WHERE t.N BETWEEN 1 AND DATALENGTH(SortPath)
GROUP BY SUBSTRING(h.SortPath,t.N,4)
) --=== Update the NodeCount and calculate the RightBower
UPDATE h
SET h.NodeCount = downline.NodeCount,
h.RightBower = (downline.NodeCount - 1) * 2 + LeftBower + 1
FROM dbo.Hierarchy h
JOIN cteCountDownlines downline
ON h.EmployeeID = downline.EmployeeID
;
that is from https://www.sqlservercentral.com/articles/hierarchies-on-steroids-1-convert-an-adjacency-list-to-nested-sets. I have tried many ways but not work. The separated cteCountDownlines and join works just fine, but don’t knwo how to conbine them
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Answer
If you are using SQLite 3.33.0+ you can use the UPDATE...FROM
syntax:
WITH cteCountDownlines AS (
SELECT CAST(SUBSTR(h.SortPath,t.N,4) AS INT) EmployeeID,
COUNT(*) NodeCount
FROM Hierarchy h INNER JOIN HTally t
ON t.N BETWEEN 1 AND LENGTH(h.SortPath)
GROUP BY SUBSTR(h.SortPath,t.N,4)
)
UPDATE Hierarchy AS h
SET NodeCount = downline.NodeCount,
RightBower = (downline.NodeCount - 1) * 2 + h.LeftBower + 1
FROM cteCountDownlines downline
WHERE h.EmployeeID = downline.EmployeeID;
For SQLite 3.15.0+ you can use this syntax:
WITH cteCountDownlines AS (
SELECT CAST(SUBSTR(h.SortPath,t.N,4) AS INT) EmployeeID,
COUNT(*) NodeCount
FROM Hierarchy h INNER JOIN HTally t
ON t.N BETWEEN 1 AND LENGTH(h.SortPath)
GROUP BY SUBSTR(h.SortPath,t.N,4)
)
UPDATE Hierarchy AS h
SET (NodeCount, RightBower) = (
SELECT downline.NodeCount,
(downline.NodeCount - 1) * 2 + h.LeftBower + 1
FROM cteCountDownlines downline
WHERE h.EmployeeID = downline.EmployeeID
);
Note that there is no equivalent to SQL Server’s DATALENGTH()
function.
The function LENGTH()
I used returns the number of chars in a string.