日考2

.gitignore

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+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### IntelliJ IDEA ###
+.idea/modules.xml
+.idea/jarRepositories.xml
+.idea/compiler.xml
+.idea/libraries/
+*.iws
+*.iml
+*.ipr
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store

.idea/.gitignore

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+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/CamelCaseConfigNew.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CamelCaseConfig">
+    <option name="cb1State" value="false" />
+    <option name="cb2State" value="false" />
+    <option name="cb3State" value="false" />
+    <option name="cb7State" value="false" />
+    <option name="model">
+      <array>
+        <option value="kebab-case" />
+        <option value="SNAKE_CASE" />
+        <option value="CamelCase" />
+        <option value="snake_case" />
+        <option value="camelCase" />
+        <option value="space case" />
+        <option value="Camel Case" />
+      </array>
+    </option>
+  </component>
+</project>

.idea/encodings.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding" defaultCharsetForPropertiesFiles="UTF-8">
+    <file url="file://$PROJECT_DIR$/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/src/main/resources" charset="UTF-8" />
+    <file url="PROJECT" charset="UTF-8" />
+  </component>
+</project>

.idea/inspectionProfiles/Project_Default.xml

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+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+  </profile>
+</component>

.idea/misc.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/pom.xml" />
+      </list>
+    </option>
+  </component>
+  <component name="ProjectInspectionProfilesVisibleTreeState">
+    <entry key="Project Default">
+      <profile-state>
+        <expanded-state>
+          <State />
+          <State>
+            <id>Android</id>
+          </State>
+          <State>
+            <id>CorrectnessLintAndroid</id>
+          </State>
+          <State>
+            <id>Gradle</id>
+          </State>
+          <State>
+            <id>Kotlin</id>
+          </State>
+          <State>
+            <id>LintAndroid</id>
+          </State>
+          <State>
+            <id>Maven</id>
+          </State>
+          <State>
+            <id>MavenMigrationKotlin</id>
+          </State>
+          <State>
+            <id>MigrationKotlin</id>
+          </State>
+          <State>
+            <id>OSGi</id>
+          </State>
+          <State>
+            <id>Probable bugsGradle</id>
+          </State>
+        </expanded-state>
+        <selected-state>
+          <State>
+            <id>Android</id>
+          </State>
+        </selected-state>
+      </profile-state>
+    </entry>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_22" default="true" project-jdk-name="22" project-jdk-type="JavaSDK" />
+</project>

pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.muyu</groupId>
+    <artifactId>rik02</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+</project>

sql/rik02 - 查询.sql

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+-- 1.创建表
+-- 学生表，t_student，字段有：学生s_id，学生姓名s_name，性别sex（5分）
+CREATE TABLE `rik02`.`t_student`  (
+  `s_id` int NOT NULL AUTO_INCREMENT COMMENT '学生id',
+  `s_name` varchar(100) NULL COMMENT '学生姓名',
+  `sex` varchar(255) NULL COMMENT '性别',
+  PRIMARY KEY (`s_id`)
+);
+-- 课程表，t_course，字段有：课程编号c_id，课程名称c_name。（5分）
+CREATE TABLE `rik02`.`t_course`  (
+  `c_id` int NOT NULL AUTO_INCREMENT COMMENT '课程编号',
+  `c_name` varchar(100) NULL COMMENT '课程名称',
+  PRIMARY KEY (`c_id`)
+);
+-- 选课表，stu_cou,字段：选课sc_id，课程编号c_id，学生s_id。（10分）
+CREATE TABLE `rik02`.`stu_cou`  (
+  `sc_id` int NOT NULL AUTO_INCREMENT COMMENT '学生id',
+  `c_id` varchar(100) NULL COMMENT '课程编号',
+  `s_id` varchar(255) NULL COMMENT '学生Id',
+  PRIMARY KEY (`sc_id`)
+);
+
+-- 2.插入数据，要求：
+-- 学生人数不少于10人。（10分）
+INSERT INTO `rik02`.`t_student`
+ (`s_name`, `sex`)
+ VALUES 
+ ( '学生1', '男'),
+ ( '学生2', '男'),
+ ( '学生3', '女'),
+ ( '学生4', '女'),
+ ( '学生5', '女'),
+ ( '学生6', '女'),
+ ( '学生7', '男'),
+ ( '学生8', '男'),
+ ( '学生9', '男'),
+ ( '学生10', '女');
+
+-- 课程数量不少于3。（5分）
+INSERT INTO `rik02`.`t_course`
+ (`c_name`) 
+VALUES 
+( '课程1'),
+( '课程2'),
+( '课程3');
+-- 每个学生可以选择多个课程，每门课程至少有3个学生。（15分）
+INSERT INTO `rik02`.`stu_cou` 
+(`c_id`, `s_id`) 
+VALUES
+ ( '1' , '2'),
+ ( '1' , '3'),
+ ( '1' , '4'),
+ ( '2' , '4'),
+ ( '3' , '4'),
+ ( '1' , '6'),
+ ( '2' , '6'),
+ ( '3' , '6'),
+ ( '1' , '7'),
+ ( '1' , '8'),
+ ( '1' , '9'),
+ ( '2' , '7'),
+ ( '2' , '9'),
+ ( '3' ,'10');
+ 
+
+-- 3.查询男生和女生各多少人。（15分）
+select sex,count(1) FROM  t_student GROUP BY sex;
+-- 4.	查询男生和女生分别占总人数的比例。（20分）
+select sex,count(1)/(SELECT COUNT(1) FROM t_student) FROM  t_student GROUP BY sex;
+-- 5.查询每门课程下的学生总人数。（15分）
+SELECT c_name,COUNT(1) FROM `rik02`.t_course tc RIGHT JOIN `rik02`.stu_cou sc on tc.c_id = sc.c_id GROUP BY tc.c_id

sql/rik02.sql

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+/*
+ Navicat Premium Dump SQL
+
+ Source Server         : localhost_3307
+ Source Server Type    : MySQL
+ Source Server Version : 80031 (8.0.31)
+ Source Host           : localhost:3307
+ Source Schema         : rik02
+
+ Target Server Type    : MySQL
+ Target Server Version : 80031 (8.0.31)
+ File Encoding         : 65001
+
+ Date: 19/07/2024 09:04:06
+*/
+
+SET NAMES utf8mb4;
+SET FOREIGN_KEY_CHECKS = 0;
+
+-- ----------------------------
+-- Table structure for stu_cou
+-- ----------------------------
+DROP TABLE IF EXISTS `stu_cou`;
+CREATE TABLE `stu_cou`  (
+  `sc_id` int NOT NULL AUTO_INCREMENT COMMENT '学生id',
+  `c_id` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '课程编号',
+  `s_id` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '学生Id',
+  PRIMARY KEY (`sc_id`) USING BTREE
+) ENGINE = InnoDB AUTO_INCREMENT = 15 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;
+
+-- ----------------------------
+-- Records of stu_cou
+-- ----------------------------
+INSERT INTO `stu_cou` VALUES (1, '1', '2');
+INSERT INTO `stu_cou` VALUES (2, '1', '3');
+INSERT INTO `stu_cou` VALUES (3, '1', '4');
+INSERT INTO `stu_cou` VALUES (4, '2', '4');
+INSERT INTO `stu_cou` VALUES (5, '3', '4');
+INSERT INTO `stu_cou` VALUES (6, '1', '6');
+INSERT INTO `stu_cou` VALUES (7, '2', '6');
+INSERT INTO `stu_cou` VALUES (8, '3', '6');
+INSERT INTO `stu_cou` VALUES (9, '1', '7');
+INSERT INTO `stu_cou` VALUES (10, '1', '8');
+INSERT INTO `stu_cou` VALUES (11, '1', '9');
+INSERT INTO `stu_cou` VALUES (12, '2', '7');
+INSERT INTO `stu_cou` VALUES (13, '2', '9');
+INSERT INTO `stu_cou` VALUES (14, '3', '10');
+
+-- ----------------------------
+-- Table structure for t_course
+-- ----------------------------
+DROP TABLE IF EXISTS `t_course`;
+CREATE TABLE `t_course`  (
+  `c_id` int NOT NULL AUTO_INCREMENT COMMENT '课程编号',
+  `c_name` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '课程名称',
+  PRIMARY KEY (`c_id`) USING BTREE
+) ENGINE = InnoDB AUTO_INCREMENT = 4 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;
+
+-- ----------------------------
+-- Records of t_course
+-- ----------------------------
+INSERT INTO `t_course` VALUES (1, '课程1');
+INSERT INTO `t_course` VALUES (2, '课程2');
+INSERT INTO `t_course` VALUES (3, '课程3');
+
+-- ----------------------------
+-- Table structure for t_student
+-- ----------------------------
+DROP TABLE IF EXISTS `t_student`;
+CREATE TABLE `t_student`  (
+  `s_id` int NOT NULL AUTO_INCREMENT COMMENT '学生id',
+  `s_name` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '学生姓名',
+  `sex` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '性别',
+  PRIMARY KEY (`s_id`) USING BTREE
+) ENGINE = InnoDB AUTO_INCREMENT = 12 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;
+
+-- ----------------------------
+-- Records of t_student
+-- ----------------------------
+INSERT INTO `t_student` VALUES (1, '1', '男');
+INSERT INTO `t_student` VALUES (2, '学生1', '男');
+INSERT INTO `t_student` VALUES (3, '学生2', '男');
+INSERT INTO `t_student` VALUES (4, '学生3', '女');
+INSERT INTO `t_student` VALUES (5, '学生4', '女');
+INSERT INTO `t_student` VALUES (6, '学生5', '男');
+INSERT INTO `t_student` VALUES (7, '学生6', '男');
+INSERT INTO `t_student` VALUES (8, '学生7', '女');
+INSERT INTO `t_student` VALUES (9, '学生8', '女');
+INSERT INTO `t_student` VALUES (10, '学生9', '女');
+INSERT INTO `t_student` VALUES (11, '学生10', '男');
+
+SET FOREIGN_KEY_CHECKS = 1;