SqlServer无限级树形构建

DECLARE @Level INT=3

;WITH cte_parent(CategoryID,CategoryName,ParentCategoryID,Level)
AS
(
    SELECT category_id,category_name,parent_category_id,1 AS Level
    FROM TianShenLogistic.dbo.ProductCategory WITH(NOLOCK)
	WHERE category_id IN
	(
		SELECT category_id 
		FROM TianShenLogistic.dbo.ProductCategory 
		WHERE parent_category_id=0
	)
    UNION ALL
    SELECT b.category_id,b.category_name,b.parent_category_id,a.Level+1 AS Level
    FROM TianShenLogistic.dbo.ProductCategory b
    INNER JOIN cte_parent a
    ON a.CategoryID = b.parent_category_id
)

SELECT 
	CategoryID AS value,
	CategoryName as label,
	ParentCategoryID As parentId,
	Level
FROM cte_parent WHERE Level <[email protected];

public static List<LogisticsCategoryTreeEntity> GetLogisticsCategoryByParent(int? level)
        {
            if (level < 1) return null;

            var dataResult = CategoryDA.GetLogisticsCategoryByParent(level);
            var firstlevel = dataResult.Where(d => d.level == 1).ToList();
            BuildCategory(dataResult, firstlevel);
            return firstlevel;
        }

        private static void BuildCategory(List<LogisticsCategoryTreeEntity> allCategoryList, List<LogisticsCategoryTreeEntity> categoryList)
        {
            foreach (var category in categoryList)
            {
                var subCategoryList = allCategoryList.Where(c => c.parentId == category.value).ToList();
                if (subCategoryList.Count > 0)
                {
                    if (category.children == null) category.children = new List<LogisticsCategoryTreeEntity>();
                    category.children.AddRange(subCategoryList);
                    BuildCategory(allCategoryList, category.children);
                }
            }
        }