myql 查询树形表结果：说说说说的述评评论的回复

Posted 2020-08-23 鸿客

myql 查询树形表结果：说说、说说的评论、评论的回复

有三张表关联表：

用户的说说表（ixt_customer_note）

说说的评论表（ixt_customer_note_comment）

评论的回复表（ixt_customer_note_reply）

说说表保存的是用户发表的说说信息，评论表保存的是用户对说说发表的评论信息，回复表保存的是用户对评论及回复的回复

 

 要求查询三张表返回结果为树形结构，如下：

 发表说说:1003                 

 发表说说:1002                 

     发表评论:comment1002_1    

     发表评论:comment1002_2    

         发表回复:reply_1002_1 

         发表回复:reply_1002_2 

     发表评论:comment1002_3    

 发表说说:1001                 

     发表评论:comment1001_1    

     发表评论:comment1001_2    

 发表说说:1000                 

     发表评论:comment1000_1    

         发表回复:reply_1000_1 

         发表回复:reply_1000_2 

 

1、设计三张表及插入相关数据

ixt_customer_note 表结构：

ixt_customer_note 表sql语句： DROP TABLE IF EXISTS `ixt_customer_note`; CREATE TABLE `ixt_customer_note` (   `id` varchar(50) NOT NULL COMMENT ‘主键UUID‘,   `customerId` varchar(50) NOT NULL COMMENT ‘用户id‘,   `content` varchar(500) NOT NULL COMMENT ‘说说内容‘,   `createUser` varchar(50) DEFAULT NULL COMMENT ‘创建人ID‘,   `createDate` datetime DEFAULT NULL COMMENT ‘创建时间‘,   `updateUser` varchar(50) DEFAULT NULL COMMENT ‘更新人ID‘,   `updateDate` datetime DEFAULT NULL COMMENT ‘更新时间‘,   `deleteFlag` bit(1) NOT NULL DEFAULT b‘0‘ COMMENT ‘删除标识：0未删除，1删除‘,   PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;   INSERT INTO `ixt_customer_note` VALUES (‘1000‘, ‘user1‘, ‘1000‘, null, ‘2015-10-01 21:18:24‘, null, null, ‘‘); INSERT INTO `ixt_customer_note` VALUES (‘1001‘, ‘user1‘, ‘1001‘, null, ‘2015-10-06 21:18:19‘, null, null, ‘‘); INSERT INTO `ixt_customer_note` VALUES (‘1002‘, ‘user1‘, ‘1002‘, null, ‘2015-10-14 22:05:04‘, null, null, ‘‘); INSERT INTO `ixt_customer_note` VALUES (‘1003‘, ‘user1‘, ‘1003‘, null, ‘2015-10-15 21:18:12‘, null, null, ‘‘);

 

 

ixt_customer_note_comment 表结构：

ixt_customer_note_comment 表sql语句： DROP TABLE IF EXISTS `ixt_customer_note_comment`; CREATE TABLE `ixt_customer_note_comment` (   `id` varchar(50) NOT NULL COMMENT ‘主键UUID‘,   `customerId` varchar(50) NOT NULL COMMENT ‘评论用户ID‘,   `dataId` varchar(50) NOT NULL COMMENT ‘被评论的说说ID‘,   `content` varchar(1000) NOT NULL COMMENT ‘评论内容‘,   `createUser` varchar(50) DEFAULT NULL COMMENT ‘创建人ID‘,   `createDate` datetime DEFAULT NULL COMMENT ‘更新人ID‘,   `updateUser` varchar(50) DEFAULT NULL COMMENT ‘更新时间‘,   `updateDate` datetime DEFAULT NULL COMMENT ‘更新时间‘,   `deleteFlag` bit(1) NOT NULL DEFAULT b‘0‘ COMMENT ‘删除标识：0未删除，1删除‘,   PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;   INSERT INTO `ixt_customer_note_comment` VALUES (‘1111‘, ‘a1‘, ‘1001‘, ‘comment1001_1‘, null, ‘2015-10-12 21:21:22‘, null, null, ‘‘); INSERT INTO `ixt_customer_note_comment` VALUES (‘1212‘, ‘a2‘, ‘1001‘, ‘comment1001_2‘, null, ‘2015-10-12 22:21:11‘, null, null, ‘‘); INSERT INTO `ixt_customer_note_comment` VALUES (‘2121‘, ‘b3‘, ‘1002‘, ‘comment1002_3‘, null, ‘2015-10-15 21:22:48‘, null, null, ‘‘); INSERT INTO `ixt_customer_note_comment` VALUES (‘321‘, ‘b1‘, ‘1002‘, ‘comment1002_1‘, null, ‘2015-10-14 21:21:59‘, null, null, ‘‘); INSERT INTO `ixt_customer_note_comment` VALUES (‘3221‘, ‘c1‘, ‘1000‘, ‘comment1000_1‘, null, ‘2015-10-02 21:23:19‘, null, null, ‘‘); INSERT INTO `ixt_customer_note_comment` VALUES (‘421‘, ‘b2‘, ‘1002‘, ‘comment1002_2‘, null, ‘2015-10-15 21:22:25‘, null, null, ‘‘);

 

 

ixt_customer_note_reply 表结构：

ixt_customer_note_reply 表sql语句： DROP TABLE IF EXISTS `ixt_customer_note_reply`; CREATE TABLE `ixt_customer_note_reply` (   `id` varchar(50) NOT NULL COMMENT ‘主键UUID‘,   `customerId` varchar(50) NOT NULL COMMENT ‘回复用户id‘,   `commentDataId` varchar(50) DEFAULT NULL COMMENT ‘被回复的评论ID‘,   `parentReplyDataId` varchar(50) DEFAULT NULL COMMENT ‘被回复的回复的id‘,   `content` varchar(1000) NOT NULL COMMENT ‘回复内容‘,   `createUser` varchar(50) DEFAULT NULL COMMENT ‘创建人ID‘,   `createDate` datetime DEFAULT NULL COMMENT ‘更新人ID‘,   `updateUser` varchar(50) DEFAULT NULL COMMENT ‘更新时间‘,   `updateDate` datetime DEFAULT NULL COMMENT ‘更新时间‘,   `deleteFlag` bit(1) NOT NULL DEFAULT b‘0‘ COMMENT ‘删除标识：0未删除，1删除‘,   PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;   INSERT INTO `ixt_customer_note_reply` VALUES (‘1212‘, ‘v1‘, ‘3221‘, null, ‘reply_1000_1‘, null, ‘2015-10-12 21:28:44‘, null, null, ‘‘); INSERT INTO `ixt_customer_note_reply` VALUES (‘3121‘, ‘v2‘, ‘3221‘, ‘1212‘, ‘reply_1000_2‘, null, ‘2015-10-13 21:28:49‘, null, null, ‘‘); INSERT INTO `ixt_customer_note_reply` VALUES (‘431‘, ‘v3‘, ‘421‘, null, ‘reply_1002_1‘, null, ‘2015-10-14 21:28:54‘, null, null, ‘‘); INSERT INTO `ixt_customer_note_reply` VALUES (‘5231‘, ‘v4‘, ‘421‘, ‘431‘, ‘reply_1002_2‘, null, ‘2015-10-15 21:28:57‘, null, null, ‘‘);

 

2、分别查出三张表的数据：

     2.1、查询用户说说表倒序显示

select createDate, id as dataId, customerId, concat(‘发表说说:‘,content) as content from ixt_customer_note order by createDate desc;

 

     2.2、查询说说的评论正序显示

select nc.createDate, nc.dataId, nc.customerId, concat(‘发表评论:‘,nc.content) as content from ixt_customer_note_comment nc left join ixt_customer_note n on nc.dataId=n.id order by n.createDate desc, nc.createDate asc;

 

     2.3、查询说说的评论的回复正序显示

select nr.createDate, nc.dataId, nr.customerId, concat(‘发表回复:‘,nr.content) as content from ixt_customer_note_reply nr left join ixt_customer_note_comment nc on nr.commentDataId=nc.id left join ixt_customer_note n on nc.dataId=n.id order by n.createDate desc, nc.createDate asc, nr.createDate asc;

 

3、有了这三张表数据后，如何将他们显示为一张表，最终得到树形结构？

     如果想要得到树形展示，可以考虑能否将三张表返回的结果合并为一张表，因为他们的结果合并在一起后正是我们需要的所有数据，只不过最终展示的效果要调整一下。

     好的，先考虑合并用户说说及说说的评论，并按树形结构展示，这时我们应该使用 union关键字，求并集。观察一下，合并之后的结果集，应该先根据说说的发表时间倒序，再根据说说的评论的发表时间正序，所以写sql执行一下：

    大致的语句为：select * from(说说的结果集 union 评论的结果集) as T order by 说说.createDate desc, 评论.createDate asc;

 

select * from((select createDate as createDate1, "" as createDate2, id as dataId, customerId, concat(‘发表说说:‘,content) as content from ixt_customer_note order by createDate desc) union (select n.createDate as createDate1, nc.createDate as createDate2, nc.dataId, nc.customerId, concat(‘    发表评论:‘,nc.content) as content from ixt_customer_note_comment nc left join ixt_customer_note n on nc.dataId=n.id  order by n.createDate desc, nc.createDate asc)) as T order by createDate1 desc, createDate2 asc;

 

4、上面合并结果集是我们想要的结果，好的，再来合并回复结果集。合并之后的结果集应该按说说的发表时间倒序，再按评论的发表时间正序，再按回复的发表时间正序。为了区分出每条记录是哪张表的，我们在结果集中添加一个字段type，表示记录的类型：t1是说说，t2是评论，t3是回复。

     sql语句：select * from(说说的结果集 union 评论的结果集 union 回复的结果集) as T order by 说说.createDate desc, 评论.createDate asc, 回复.createDate asc;

 

select * from((select createDate as createDate1, "" as createDate2, "" as createDate3, "t1" as type, id as dataId, customerId, concat(‘发表说说:‘,content) as content from ixt_customer_note order by createDate desc) union (select n.createDate as createDate1, nc.createDate as createDate2, "" as createDate3, "t2" as type, nc.dataId, nc.customerId, concat(‘    发表评论:‘,nc.content) as content from ixt_customer_note_comment nc left join ixt_customer_note n on nc.dataId=n.id  order by n.createDate desc, nc.createDate asc) union (select n.createDate as createDate1, nc.createDate as createDate2, nr.createDate as createDate3, "t3" as type, nc.dataId, nr.customerId, concat(‘        发表回复:‘,nr.content) as content from ixt_customer_note_reply nr left join ixt_customer_note_comment nc on nr.commentDataId=nc.id left join ixt_customer_note n on nc.dataId=n.id order by n.createDate desc, nc.createDate asc, nr.createDate asc)) as T order by createDate1 desc, createDate2 asc, createDate3 asc;

 

5、上面结果集是我们想要的，不过createDate最终应该只有一个，可以继续改进，将createDate合并为一列，说说显示createDate1，评论显示createDate2，回复显示createDate3。

     改进后的语句如下：

select if(T.type=‘t1‘,T.createDate1,(if(T.type=‘t2‘,T.createDate2,T.createDate3))) as createDate, T.type, T.dataId, T.customerId, T.content from((select createDate as createDate1, "" as createDate2, "" as createDate3, "t1" as type,customerId, id as dataId, concat(‘发表说说:‘,content) as content from ixt_customer_note order by createDate desc) union (select n.createDate as createDate1, nc.createDate as createDate2, "" as createDate3, "t2" as type, nc.customerId, nc.dataId, concat(‘    发表评论:‘,nc.content) as content from ixt_customer_note_comment nc left join ixt_customer_note n on nc.dataId=n.id  order by n.createDate desc, nc.createDate asc) union (select n.createDate as createDate1, nc.createDate as createDate2, nr.createDate as createDate3, "t3" as type, nr.customerId, nc.dataId, concat(‘        发表回复:‘,nr.content) as content from ixt_customer_note_reply nr left join ixt_customer_note_comment nc on nr.commentDataId=nc.id left join ixt_customer_note n on nc.dataId=n.id order by n.createDate desc, nc.createDate asc, nr.createDate asc)) as T order by createDate1 desc, createDate2 asc, createDate3 asc;