递归取根节点，大家看下是这样吗

create function GetPath
(
        @id uniqueidentifier
)
returns nvarchar(500)
as
begin
        declare @str nvarchar(500)
        declare @pid uniqueidentifier
        select @str=category,@pid=pid from category where id=@id
        if @pid is not null
        begin
                set @str=dbo.GetPath(@pid)+','+@str
        end
        return @str
end
go
select dbo.GetPath(id) as namePath from category

drop function dbo.GetPath

表结构

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