サンプルデータ:
このクエリを使用して、親子関係を平坦化できます。
助けて...
前もって感謝します。
次のことを試してください。
select
COALESCE(mg4.Id, mg3.Id, mg2.Id, mg1.Id, em.Id) AS cat1ID,
COALESCE(mg4.Name, mg3.Name, mg2.Name, mg1.Name, em.Name) AS cat1Name,
CASE
WHEN mg4.Id IS NOT NULL THEN mg3.Id
WHEN mg3.Id IS NOT NULL THEN mg2.Id
WHEN mg2.Id IS NOT NULL THEN mg1.Id
WHEN mg1.Id IS NOT NULL THEN em.Id
END AS cat3ID,
CASE
WHEN mg4.Id IS NOT NULL THEN mg3.Name
WHEN mg3.Id IS NOT NULL THEN mg2.Name
WHEN mg2.Id IS NOT NULL THEN mg1.Name
WHEN mg1.Id IS NOT NULL THEN em.Name
END AS cat3Name,
CASE
WHEN mg4.Id IS NOT NULL THEN mg2.Id
WHEN mg3.Id IS NOT NULL THEN mg1.Id
WHEN mg2.Id IS NOT NULL THEN em.Id
END AS cat3ID,
CASE
WHEN mg4.Id IS NOT NULL THEN mg2.Name
WHEN mg3.Id IS NOT NULL THEN mg1.Name
WHEN mg2.Id IS NOT NULL THEN em.Name
END AS cat3Name,
CASE
WHEN mg4.Id IS NOT NULL THEN mg1.Id
WHEN mg3.Id IS NOT NULL THEN em.Id
END AS cat4ID,
CASE
WHEN mg4.Id IS NOT NULL THEN mg1.Name
WHEN mg3.Id IS NOT NULL THEN em.Name
END AS cat4Name,
CASE WHEN mg4.Id IS NOT NULL THEN em.Id END AS cat5ID,
CASE WHEN mg4.Id IS NOT NULL THEN em.Name END AS cat5Name,
em.Id AS chosenCatId,
CASE WHEN em.id > 0 THEN 1 ELSE 0 END
+ CASE WHEN mg1.id > 0 THEN 1 ELSE 0 END
+ CASE WHEN mg2.id > 0 THEN 1 ELSE 0 END
+ CASE WHEN mg3.id > 0 THEN 1 ELSE 0 END
+ CASE WHEN mg4.id > 0 THEN 1 ELSE 0 END AS chosenLevel
from tempCategory em
left join tempCategory mg1
on mg1.Id = em.parentCategory
left join tempCategory mg2
on mg2.Id = mg1.parentCategory
left join tempCategory mg3
on mg3.Id = mg2.parentCategory
left join tempCategory mg4
on mg4.Id = mg3.parentCategory
クエリは から列をプルしないため、最後の結合を省略しましたmg5
。
SQL Fiddle でのこのクエリ: http://sqlfiddle.com/#!3/a6f01/5
純粋な T-SQL 自体は再帰クエリをサポートしていませんが、SQL Server Common Table Expression (SQL Server のみの機能) を使用できます。
SQL-Server CTE 再帰をカバーするページは次のとおりです: http://msdn.microsoft.com/en-us/library/ms186243(v=sql.105).aspx