SQL SERVER树形结构数据——批量删除分组数据

定义函数获取某结点下所有子结点：

CREATE FUNCTION [dbo].[fn_GetSubGroupInfoById]
(
    @id AS INT    --某分组Id
)
RETURNS @SubGroups TABLE
(
    [GroupId] INT,
    [ParentGroupId] INT,
    [Level] INT
)
AS
BEGIN 
    DECLARE @level AS INT
    
    SELECT @level = 0
    
    INSERT INTO @SubGroups
    SELECT [GroupId], [ParentGroupId], @level AS [Level] 
    FROM [tbl_sysGroup] 
    WHERE [GroupId] = @id

    WHILE @@ROWCOUNT > 0 
    BEGIN
        SET @level = @level + 1

        INSERT INTO @SubGroups
        SELECT G.[GroupId], G.[ParentGroupId], @level AS [Level]
        FROM [tbl_sysGroup] AS G JOIN @SubGroups AS S
        ON G.[ParentGroupId] = S.[GroupId] AND S.[Level] = @level - 1
    END
    RETURN
END
GO

定义函数利用上面的函数收集要删除的数据：

CREATE FUNCTION [dbo].[fn_GetSubGroupInfoByIds]
(
    @ids AS NVARCHAR(256)    --逗号分割的分组Id
)
RETURNS @RetIds TABLE
(
    [GroupId] INT
)
AS
BEGIN 
    DECLARE @next INT  
    DECLARE @SubGroups TABLE
    (
        [GroupId] INT
    )

    SET @next=1
    
    WHILE @next<=dbo.fn_str_GetArrayLength(@ids,',')
    BEGIN
        INSERT INTO @SubGroups 
        SELECT [GroupId] 
        FROM dbo.fn_GetSubGroupInfoById(dbo.fn_str_GetFromArrayByIndex(@ids,',',@next))

        SET @next=@next+1
    END

    INSERT INTO @RetIds SELECT DISTINCT [GroupId] FROM @SubGroups

    RETURN
END
GO

因为是要批量删除，但是SQL里没有数组这种数据类型，所以这里利用字符串，把其当作数组来使用，但是需要两个自定义函数：

——获取数组长度：

CREATE FUNCTION [dbo].[fn_str_GetArrayLength]
(
    @str NVARCHAR(1024),    --要分割的字符串
    @split NVARCHAR(10)        --分隔符号
)
RETURNS INT
AS
BEGIN
    DECLARE @location INT
    DECLARE @start INT
    DECLARE @length INT
    SET @str=LTRIM(RTRIM(@str))
    SET @location=CHARINDEX(@split,@str)
    SET @length=1
    WHILE @location<>0
    BEGIN
        SET @start=@location+1
        SET @location=CHARINDEX(@split,@str,@start)
        SET @length=@length+1
    END
    RETURN @length
END
GO

——获取数组某位置的元素：

CREATE FUNCTION [dbo].[fn_str_GetFromArrayByIndex]
(
    @str NVARCHAR(1024),    --要分割的字符串
    @split NVARCHAR(10),    --分隔符号
    @index INT                --取第几个元素
)
RETURNS NVARCHAR(1024)
AS
BEGIN
    DECLARE @location INT
    DECLARE @start INT
    DECLARE @next INT
    DECLARE @seed INT
    SET @str=LTRIM(RTRIM(@str))
    SET @start=1
    SET @next=1
    SET @seed=LEN(@split)
    SET @location=CHARINDEX(@split,@str)
    while @location<>0 and @index>@next
    BEGIN
        SET @start=@location+@seed
        SET @location=CHARINDEX(@split,@str,@start)
        SET @next=@next+1
    END
    IF @location =0 SELECT @location =LEN(@str)+1

    --这儿存在两种情况：
    -- 1、字符串不存在分隔符号 
    -- 2、字符串中存在分隔符号，跳出while循环后，@location为0，那默认为字符串后边有一个分隔符号。
    RETURN SUBSTRING(@str,@start,@location-@start)
END
GO

定义存储过程批量删除数据：

CREATE PROCEDURE [dbo].[sp_DeleteSubGroupById]
    @ids NVARCHAR(256)    --逗号分割的分组Id
AS
BEGIN
    DELETE FROM [dbo].[tbl_sysGroup] 
    WHERE [GroupId] in 
    (
        SELECT [GroupId] 
        FROM [dbo].[fn_GetSubGroupInfoByIds](@ids)
    )
    RETURN @@ROWCOUNT
END
GO

这样在EF上添加存储过程后直接传入逗号分割的id字符串就可以批量删除了。返回值是受影响的条数