commit 289ac459cf757632bdcb38d9c3db5552c62fc076 Author: zzh <2441574824@qq.com> Date: Fri Jul 19 09:27:26 2024 +0800 日考2 diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..3e403e3 --- /dev/null +++ b/.gitignore @@ -0,0 +1,35 @@ +target/ +!.mvn/wrapper/maven-wrapper.jar +!**/src/main/**/target/ +!**/src/test/**/target/ + +### IntelliJ IDEA ### +.idea +*.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 diff --git a/.idea/$PROJECT_FILE$ b/.idea/$PROJECT_FILE$ new file mode 100644 index 0000000..58b7e3e --- /dev/null +++ b/.idea/$PROJECT_FILE$ @@ -0,0 +1,11 @@ + + + + + + + \ No newline at end of file diff --git a/.idea/.gitignore b/.idea/.gitignore new file mode 100644 index 0000000..13566b8 --- /dev/null +++ b/.idea/.gitignore @@ -0,0 +1,8 @@ +# Default ignored files +/shelf/ +/workspace.xml +# Editor-based HTTP Client requests +/httpRequests/ +# Datasource local storage ignored files +/dataSources/ +/dataSources.local.xml diff --git a/.idea/encodings.xml b/.idea/encodings.xml new file mode 100644 index 0000000..63574ec --- /dev/null +++ b/.idea/encodings.xml @@ -0,0 +1,8 @@ + + + + + + + + \ No newline at end of file diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml new file mode 100644 index 0000000..8d66637 --- /dev/null +++ b/.idea/inspectionProfiles/Project_Default.xml @@ -0,0 +1,5 @@ + + + + \ No newline at end of file diff --git a/.idea/misc.xml b/.idea/misc.xml new file mode 100644 index 0000000..b4d5a88 --- /dev/null +++ b/.idea/misc.xml @@ -0,0 +1,17 @@ + + + + + + + + + + + + \ No newline at end of file diff --git a/.idea/qaplug_profiles.xml b/.idea/qaplug_profiles.xml new file mode 100644 index 0000000..9a7566c --- /dev/null +++ b/.idea/qaplug_profiles.xml @@ -0,0 +1,12 @@ + + + + + \ No newline at end of file diff --git a/pom.xml b/pom.xml new file mode 100644 index 0000000..01db0ae --- /dev/null +++ b/pom.xml @@ -0,0 +1,17 @@ + + + 4.0.0 + + org.example + rikao2 + 1.0-SNAPSHOT + + + 8 + 8 + UTF-8 + + + diff --git a/sql/rikao2.sql b/sql/rikao2.sql new file mode 100644 index 0000000..7c1ad37 --- /dev/null +++ b/sql/rikao2.sql @@ -0,0 +1,74 @@ + + +-- 3.查询男生和女生各多少人。（15分） +SELECT sex,count(*) 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,ROUND(count(*)/(SELECT count(*) FROM t_student),2) FROM t_student GROUP BY sex + +-- 5.查询每门课程下的学生总人数。（15分） +SELECT + c.c_name,count(*) +FROM + t_student s + LEFT JOIN stu_cou sc on s.s_id = sc.s_id + LEFT JOIN t_course c on c.c_id = sc.c_id GROUP BY c.c_id + + + + +CREATE TABLE `t_student` ( + `s_id` int NOT NULL AUTO_INCREMENT, + `s_name` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL, + `sex` varchar(2) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL, + PRIMARY KEY (`s_id`) USING BTREE +) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic; + +-- Records of t_student +-- ---------------------------- +INSERT INTO `t_student` VALUES (1, '张三', '男'); +INSERT INTO `t_student` VALUES (2, '李四', '男'); +INSERT INTO `t_student` VALUES (3, '王五', '男'); +INSERT INTO `t_student` VALUES (4, '赵六', '男'); +INSERT INTO `t_student` VALUES (5, '田七', '男'); +INSERT INTO `t_student` VALUES (6, '崔八', '男'); +INSERT INTO `t_student` VALUES (7, '春兰', '女'); +INSERT INTO `t_student` VALUES (8, '夏竹', '女'); +INSERT INTO `t_student` VALUES (9, '秋叶', '女'); +INSERT INTO `t_student` VALUES (10, '冬梅', '女'); + + +CREATE TABLE `t_course` ( + `c_id` int NOT NULL AUTO_INCREMENT, + `c_name` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL, + PRIMARY KEY (`c_id`) USING BTREE +) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic; + + +INSERT INTO `t_course` VALUES (1, '语文'); +INSERT INTO `t_course` VALUES (2, '数学'); +INSERT INTO `t_course` VALUES (3, '英语'); + + + +CREATE TABLE `stu_cou` ( + `sc_id` int NOT NULL AUTO_INCREMENT, + `c_id` int NULL DEFAULT NULL, + `s_id` int NULL DEFAULT NULL, + PRIMARY KEY (`sc_id`) USING BTREE +) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic; + + +INSERT INTO `stu_cou` VALUES (1, 1, 1); +INSERT INTO `stu_cou` VALUES (2, 1, 2); +INSERT INTO `stu_cou` VALUES (3, 1, 3); +INSERT INTO `stu_cou` VALUES (4, 2, 4); +INSERT INTO `stu_cou` VALUES (5, 2, 6); +INSERT INTO `stu_cou` VALUES (6, 2, 5); +INSERT INTO `stu_cou` VALUES (7, 3, 7); +INSERT INTO `stu_cou` VALUES (8, 3, 8); +INSERT INTO `stu_cou` VALUES (9, 3, 9); +INSERT INTO `stu_cou` VALUES (10, 3, 10); + + + \ No newline at end of file diff --git a/src/main/java/org/example/Main.java b/src/main/java/org/example/Main.java new file mode 100644 index 0000000..1074273 --- /dev/null +++ b/src/main/java/org/example/Main.java @@ -0,0 +1,13 @@ +package org.example; + +/** + * @Author：zhangzhihao + * @name：${NAME} + * @Date：2024/7/19 9:13 + * 不准抄代码，添加注释，清楚每一行代码意思 + */ +public class Main { + public static void main(String[] args) { + System.out.println("Hello world!"); + } +}