一道关于数据库(经典父子级 ID 关联)更新题

with cte(areacode,areaName,content) as
(
--- 查询 ParentCode 为 0 （ParentCode 为 0 的为顶级菜单）
select areacode,areaName,cast(areaName as varchar(50)) AS content
from [AreaRegion] where parentcode=0
union all
-- 再进行递归查询
select a.areacode,a.areaName,cast(a.content+','+b.areaName as varchar(50） AS content 9 from [AreaRegion] a 10 inner join cte b on a.parentcode=b.areacode )
select * from cte

USE JKCRM
GO
--定义游标
DECLARE updateCursor CURSOR SCROLL FOR
SELECT A.AreaCode FROM DBO.AreaRegion A
--打开游标
OPEN updateCursor
--定义变量 存储依次获取游标值
DECLARE @aID NVARCHAR(30)=''
---定义变量 存储父结点具体信息
DECLARE @pStr NVARCHAR(300)='';
--定义表变量 存储两字段 AreaCode Content ( Content :为该字段所有父级菜单信息)
DECLARE @TempTable TABLE
(
AreaCode INT PRIMARY KEY,
Content NVARCHAR(3000)
)
--首次获取游标第一个值 插入变量 @AID
FETCH FIRST FROM updateCursor INTO @AID
 
WHILE(@@FETCH_STATUS=0)
BEGIN
--PRINT(@AID) ;
---通过传入的 @AID ,查询其所有父级菜单信息
WITH TB AS
(
---递归查询父子菜单信息 公用表表达式递归查询
SELECT A.*,0 AS LEVEL FROM JKCRM.DBO.AreaRegion A
WHERE A.AreaCode=@AID
UNION ALL
SELECT B.* ,LEVEL+1 AS LEVEL FROM TB A INNER JOIN JKCRM.DBO.AreaRegion B
ON A.ParentCode=B.AreaCode
)
---再将查询的表信息 拼接成字符串 此处 即采用 SELECT 循环查询
SELECT @pStr=@pStr+ CASE
WHEN @pStr='' THEN TB.AreaName ELSE ','+TB.AreaName END
FROM TB ORDER BY TB.LEVEL ASC
-- PRINT(@pSTR)
--插入表变量
INSERT INTO @TempTable SELECT @aID,@pStr
---将此次通过 AreaCode 获取的该节点 @pStr 置空
SET @pStr=''
FETCH NEXT FROM updateCursor INTO @AID
END
 
--SELECT B.AreaCode,B.AreaName,B.ParentCode,A.Content,A.AreaCode
--FROM @TempTable A RIGHT JOIN DBO.AreaRegion B ON A.AreaCode=B.AreaCode ORDER BY B.AreaCode
 
---此处 即可进行 UPDATE 更新操作
UPDATE A SET A.Content=B.Content FROM DBO.AreaRegion A
INNER JOIN @TempTable B ON A.AreaCode=B.AreaCode
 
--关闭释放游标
CLOSE updateCursor
DEALLOCATE updateCursor

/*
Navicat SQL Server Data Transfer
 
Source Server : SQL
Source Server Version : 120000
Source Host : .:1433
Source Database : JKCRM
Source Schema : dbo
 
Target Server Type : SQL Server
Target Server Version : 120000
File Encoding : 65001
 
Date: 2015-06-12 11:20:40
*/
 
 
-- ----------------------------
-- Table structure for AreaRegion
-- ----------------------------
DROP TABLE [dbo].[AreaRegion]
GO
CREATE TABLE [dbo].[AreaRegion] (
[AreaCode] varchar(10) NOT NULL ,
[AreaName] varchar(50) NULL ,
[ParentCode] varchar(10) NULL ,
[Content] nvarchar(200) NULL
)
 
 
GO
 
-- ----------------------------
-- Records of AreaRegion
-- ----------------------------
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110000', N'北京市', N'0', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110100', N'东城区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110200', N'西城区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110300', N'崇文区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110400', N'宣武区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110500', N'朝阳区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110600', N'丰台区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110700', N'石景山区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110800', N'海淀区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'110900', N'门头沟区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'111000', N'房山区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'111100', N'通州区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'111200', N'顺义区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'111300', N'昌平区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'111400', N'大兴区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'111500', N'怀柔区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'111600', N'平谷区', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'111700', N'密云县', N'110000', null)
GO
GO
INSERT INTO [dbo].[AreaRegion] ([AreaCode], [AreaName], [ParentCode], [Content]) VALUES (N'111800', N'延庆县', N'110000', null)