select高级——子查询

定义

子查询是在一个查询的内部包括另一个查询的查询方式。

简单子查询案例

select * 
from `comment` 
where cmtDate > 
(select cmtDate from `comment` where cmtAuthor = '东东1')

IN和NOT IN子查询

IN案例

查询名字中包含’东‘的作者评论过的所有新闻

SELECT * FROM news
WHERE id 
IN 
(SELECT newsId FROM `comment` WHERE cmtAuthor LIKE '%东%')

NOT IN案例
查询名字中不包含’东‘的作者评论过的所有新闻

SELECT * FROM news
WHERE id 
NOT IN 
(SELECT newsId FROM `comment` WHERE cmtAuthor LIKE '%东%')

ANY / SOME子查询

SELECT * FROM news
WHERE id = 
ANY
(SELECT newsId FROM `comment` WHERE cmtAuthor LIKE '%东%')

ALL子查询

SELECT * FROM news
WHERE id >= 
ALL
(SELECT newsId FROM `comment` WHERE cmtAuthor LIKE '%东%')

数据库代码

/*
 Navicat Premium Data Transfer

 Source Server         : 192.168.0.102
 Source Server Type    : MySQL
 Source Server Version : 50720
 Source Host           : 192.168.0.102
 Source Database       : test_select

 Target Server Type    : MySQL
 Target Server Version : 50720
 File Encoding         : utf-8

 Date: 09/23/2021 08:36:24 AM
*/

SET NAMES utf8;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
--  Table structure for `comment`
-- ----------------------------
DROP TABLE IF EXISTS `comment`;
CREATE TABLE `comment` (
  `cmtId` int(4) NOT NULL AUTO_INCREMENT,
  `newsId` int(4) NOT NULL,
  `cmtContent` varchar(100) NOT NULL,
  `cmtDate` datetime NOT NULL,
  `cmtIP` varchar(20) NOT NULL,
  `cmtAuthor` varchar(20) DEFAULT NULL,
  PRIMARY KEY (`cmtId`),
  KEY `newsId` (`newsId`),
  CONSTRAINT `comment_ibfk_1` FOREIGN KEY (`newsId`) REFERENCES `news` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=21 DEFAULT CHARSET=utf8;

-- ----------------------------
--  Records of `comment`
-- ----------------------------
BEGIN;
INSERT INTO `comment` VALUES ('1', '1', '有深度', '2019-01-01 00:00:00', '192.168.1.2', '张三1'), ('2', '1', '有深度', '2018-12-03 00:00:00', '192.168.1.2', '张三2'), ('3', '1', '有深度', '2019-12-03 00:00:00', '192.168.1.2', '张三3'), ('4', '2', '娱乐圈真乱！', '2018-12-13 00:00:00', '192.168.1.3', '小豆豆1'), ('5', '2', '娱乐圈真乱！', '2018-12-13 00:00:00', '192.168.1.3', '小豆豆2'), ('6', '3', '我喜欢孙俪', '2018-12-20 00:00:00', '192.168.1.4', '东东1'), ('7', '3', '我喜欢孙俪', '2018-12-20 00:00:00', '192.168.1.4', '东东2'), ('8', '3', '我喜欢孙俪', '2018-12-20 00:00:00', '192.168.1.4', '东东3'), ('9', '3', '我喜欢孙俪', '2018-12-20 00:00:00', '192.168.1.4', '东东4'), ('10', '1', '我喜欢孙俪', '2018-12-20 00:00:00', '192.168.1.4', '东东5'), ('16', '1', '有深度', '2018-12-03 00:00:00', '192.168.1.2', '张三'), ('17', '1', '我爱邓超', '2018-12-27 00:00:00', '192.168.1.5', '张三1'), ('18', '1', '有深度', '2018-12-03 00:00:00', '192.168.1.2', '张三'), ('19', '1', '有深度', '2018-12-03 00:00:00', '192.168.1.2', null), ('20', '1', '有深度', '2018-12-03 00:00:00', '192.168.1.2', '');
COMMIT;

-- ----------------------------
--  Table structure for `news`
-- ----------------------------
DROP TABLE IF EXISTS `news`;
CREATE TABLE `news` (
  `id` int(4) NOT NULL AUTO_INCREMENT,
  `newsTitle` varchar(20) NOT NULL,
  `topicId` int(4) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `topicId` (`topicId`),
  CONSTRAINT `news_ibfk_1` FOREIGN KEY (`topicId`) REFERENCES `topic` (`topicId`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

-- ----------------------------
--  Records of `news`
-- ----------------------------
BEGIN;
INSERT INTO `news` VALUES ('1', '切尔西', '1'), ('2', '正发朋友圈怒怼《演员的品格》', '2'), ('3', '太饿了！孙俪机智骗取某某同学午餐充饥', '2');
COMMIT;

-- ----------------------------
--  Table structure for `topic`
-- ----------------------------
DROP TABLE IF EXISTS `topic`;
CREATE TABLE `topic` (
  `topicId` int(4) NOT NULL AUTO_INCREMENT,
  `topicName` varchar(20) NOT NULL,
  PRIMARY KEY (`topicId`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

-- ----------------------------
--  Records of `topic`
-- ----------------------------
BEGIN;
INSERT INTO `topic` VALUES ('1', '体育'), ('2', '娱乐'), ('3', '经济');
COMMIT;

SET FOREIGN_KEY_CHECKS = 1;