2025-02-06

2025-02-06 22:43:19 +08:00
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+### MySQL-1
+
+```sql
+#1.添加字段
+ALTER TABLE t_student ADD descr VARCHAR(200) DEFAULT '无';
+
+#2.插入记录
+INSERT INTO t_student()
+VALUES(DEFAULT, '林小莉', '女', 8, 10005,'13971555555',  '身体瘦弱，训练强度需要调整');
+
+#3.简单查询 tj11
+SELECT c.id, c.`name`, CONCAT(YEAR(c.time),'年',MONTH(c.time),'月', DAY(c.time),'日')
+FROM t_class c;
+
+
+#4.排序、分页查询 tj12
+SELECT *
+FROM t_coach c
+ORDER BY c.salary
+LIMIT 1, 2;
+
+#5.模糊、多表连接查询 tj13
+SELECT co.`name`, cl.`name`, cl.period
+FROM t_coach co, t_class cl
+WHERE co.id = cl.coachId AND co.`name` LIKE '何%';
+
+#6.更新记录
+UPDATE t_coach c
+SET c.salary = c.salary + 200
+WHERE c.age >= 30;
+
+#7.多表联查+视图
+CREATE VIEW v_swim AS
+SELECT s.`name` '学员姓名', co.`name` '教练姓名', cl.`name` '班级名称'
+FROM t_student s, t_class cl, t_coach co
+WHERE s.classId = cl.id AND cl.coachId = co.id;
+
+#8.插入操作的触发器
+DELIMITER $$
+DROP TRIGGER IF EXISTS tri_familylog;
+CREATE TRIGGER tri_familylog
+AFTER DELETE ON t_family
+FOR EACH ROW
+BEGIN
+	INSERT INTO t_log()
+	VALUES(DEFAULT, OLD.fid, '删除家庭', '2024-01-01');
+END $$
+DELIMITER ;
+
+#9.条件查询+聚合函数 存储过程
+DELIMITER $$
+DROP PROCEDURE IF EXISTS pro_getStudentNumber;
+CREATE PROCEDURE pro_getStudentNumber(IN in_classId INT, OUT out_number INT)
+BEGIN
+	SELECT COUNT(*) INTO out_number
+	FROM t_student s
+	WHERE s.classId = in_classId;
+END $$
+DELIMITER ;
+
+#测试存储过程
+CALL pro_getStudentNumber(10002, @result);
+SELECT @result;
+```
+
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+### C语言-1
+
+```c
+/*------------------------------------------------------------------------------
+（1）【程序设计】定义一个大小为50的整型数组，将数字1~50存入该数组，利用指针将数组中的值输出，每行5个，每个数字占4个符号位，左对齐。
+------------------------------------------------------------------------------*/
+#include <stdio.h>
+#include <stdlib.h>
+int main()
+{
+	int i,*p,array[50];
+	for(i=0;i<50;i++)
+	{
+		array[i]=i+1;
+	}
+	p=array;
+/**********Program**********/
+	for(i=0;i<50;i++){
+		//p指针变量 存着数组array首元素地址
+		printf("%-4d ", *(p+i));//*间接访问符 用来返回指针所指向数值
+		if((i+1)%5==0){
+			printf("\n");
+		}
+	}
+/**********  End  **********/
+}
+```
+
+### C语言-2
+
+```c
+/*----------------------------------------------------------------------
+【程序设计】
+------------------------------------------------------------------------
+题目：要求实现一个函数，能够合并两个整数数组,合并后进行降序排序并删除重复元素。
+示例1：
+输入输出如下所示：
+请输入第一个数组的6个元素，每个元素之间用空格隔开：1 3 5 7 10 6
+请输入第二个数组的6个元素，每个元素之间用空格隔开：10 4 2 6 11 30
+合并后降序排列的数组：30 11 10 7 6 5 4 3 2 1
+------------------------------------------------------------------------
+注意：请勿改动程序中的其他内容。
+----------------------------------------------------------------------*/
+#include <stdio.h>
+
+int* mergeArrays(int *arr1, int size1, int *arr2, int size2,int *newLen);
+
+int main() {
+
+        int size1=6;
+	int size2=6;
+	int arr1[6];
+	int arr2[6];
+	int i;
+
+	int newLen = 0;
+	int* mergedArray;
+
+	printf("请输入第一个数组的6个元素，每个元素之间用空格隔开：");
+	for ( i = 0; i < size1; i++) {
+            scanf("%d", &arr1[i]);
+        }
+	printf("请输入第二个数组的6个元素，每个元素之间用空格隔开：");
+	for ( i = 0; i < size2; i++) {
+            scanf("%d", &arr2[i]);
+        }
+
+	mergedArray = mergeArrays(arr1, size1, arr2, size2, &newLen);
+
+	printf("合并后降序排列的数组：");
+	for (i = 0; i < newLen; i++) {
+	    printf("%d ", mergedArray[i]);
+	}
+	printf("\n");
+	return 0;
+}
+
+
+int* mergeArrays(int *arr1,int size1,int *arr2,int size2,int *newLen) {
+	static int mergedArray[20];
+	/**********Program**********/
+	//将两个数组中的元素合并到一个新的数组里
+	int i, j=0, temp;
+	*newLen = 1;
+	//合并
+	for(i=0;i<6;i++){
+		mergedArray[j++] = arr1[i];
+		mergedArray[j++] = arr2[i];
+	}
+	//排序
+	for(i=0;i<size1*2-1;i++){
+		for(j=0;j<size1*2-1-i;j++){
+			if(mergedArray[j] < mergedArray[j+1]){
+				temp = mergedArray[j];
+				mergedArray[j] = mergedArray[j+1];
+				mergedArray[j+1] = temp;
+			}
+		}
+	}
+	//去重
+	for(i=1;i<size1*2;i++){
+		if(mergedArray[(*newLen)- 1] != mergedArray[i]){
+			mergedArray[(*newLen)++] =  mergedArray[i];
+		}
+	}
+
+	/**********  End  **********/
+	return mergedArray;
+}
+```
+
+### 数据库-1
+
+```sql
+#1. 设置字段主键+自动增长
+ALTER TABLE t_user MODIFY uid INT(11) PRIMARY KEY AUTO_INCREMENT;
+
+#2. 插入记录
+INSERT INTO t_user()
+VALUES(DEFAULT, 'mike', 'mm123', '小明', DEFAULT);
+
+#3. 更新记录
+UPDATE t_user u
+SET u.`password` = '888888'
+WHERE u.username = 'Dennis';
+
+#4. tj11 条件查询+多表联查
+SELECT u.nickname, c.mid, c.score, c.content
+FROM t_user u, t_comment c
+WHERE u.uid = c.uid AND u.nickname = '白色';
+
+#5. tj12 分组查询+多表联查
+SELECT m.mname, ROUND(AVG(c.score), 2)
+FROM t_movie m, t_comment c
+WHERE m.mid = c.mid
+GROUP BY m.mid;
+
+#6. tj13 分组查询+多表联查
+SELECT m.mname, COUNT(*)
+FROM t_movie m, t_comment c
+WHERE m.mid = c.mid
+GROUP BY m.mid;
+
+#7 视图 多表联查
+CREATE VIEW v_movie AS
+SELECT m.mname, u.nickname, c.score, c.content
+FROM t_user u, t_movie m , t_comment c
+WHERE u.uid = c.uid AND m.mid = c.mid;
+
+#8 存储过程
+DELIMITER $$
+DROP PROCEDURE IF EXISTS pro_getUserNumber;
+CREATE PROCEDURE pro_getUserNumber(IN in_uid INT, OUT out_number INT)
+BEGIN
+	SET out_number = (
+		SELECT COUNT(*) 
+		FROM t_user u, t_comment c
+		WHERE u.uid = c.uid AND u.uid = in_uid
+	);    
+END $$
+DELIMITER ;
+
+#9 触发器
+DELIMITER $$
+DROP TRIGGER IF EXISTS tri_userlog;
+CREATE TRIGGER tri_userlog 
+AFTER INSERT ON t_user
+FOR EACH ROW
+BEGIN
+	INSERT INTO t_log()
+	VALUES(DEFAULT, NEW.uid, '新增用户', '2024-01-01');
+END $$
+DELIMITER ;
+```
+
+### 数据库-2
+
+```sql
+
+```
+
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+### 数据库-1
+
+```sql
+#1 添加字段
+ALTER TABLE t_customer ADD integral INT(10) DEFAULT 0;
+
+#2 插入记录
+INSERT INTO t_goods()
+VALUES(10011, '口香糖', 2.5, 10, '零食');
+
+#3 tj11 排序+分页+子查询查询
+#先将第五个的库存数量查询出来 LIMIT 起始位置(从0开始), 取的个数;
+SELECT g1.gname, g1.stock
+FROM t_goods g1
+WHERE g1.stock <= (
+	SELECT g2.stock
+	FROM t_goods g2
+	ORDER BY g2.stock
+	LIMIT 4, 1
+)
+ORDER BY g1.stock;
+
+#4 tj12 子查询
+SELECT g1.gname, g1.type, g1.price
+FROM t_goods g1
+WHERE g1.price = (
+	SELECT MIN(g2.price)
+	FROM t_goods g2
+	WHERE g2.type = g1.type
+);
+
+#5 tj13 分组查询
+SELECT o.ono, g.gname, o.num * g.price, o.otime
+FROM t_order o, t_goods g
+WHERE o.gno = g.gno;
+
+#6 tj14 排序查询+连接查询
+SELECT c.cno, c.cname, o.ono, o.gno, o.num, o.otime
+FROM t_customer c, t_order o
+WHERE c.cno = o.cno AND c.cname = '龙睿'
+ORDER BY o.otime DESC;
+
+#7 排序查询+分组查询+连接查询
+CREATE VIEW v_order AS
+SELECT o.ono, c.cname, g.gname, o.num, o.otime
+FROM t_customer c, t_order o, t_goods g
+WHERE c.cno = o.cno AND o.gno = g.gno
+ORDER BY o.otime DESC
+LIMIT 49, 31;
+
+#8 触发器
+DELIMITER $$
+DROP TRIGGER IF EXISTS tri_customerlog;
+CREATE TRIGGER tri_customerlog
+AFTER UPDATE ON t_customer
+FOR EACH ROW
+BEGIN
+	INSERT INTO t_log()
+	VALUES(DEFAULT, NEW.cno, '更新客户信息', '2024-06-06');
+END $$
+DELIMITER ;
+
+#9 存储过程
+DELIMITER $$
+DROP PROCEDURE IF EXISTS pro_getSaleNumber;
+CREATE PROCEDURE pro_getSaleNumber(IN in_gno CHAR(10), OUT out_number INT)
+BEGIN
+	SELECT COUNT(DISTINCT cno) INTO out_number
+	FROM t_order
+	WHERE gno = in_gno;
+END $$
+DELIMITER ;
+
+#测试
+CALL pro_getSaleNumber(10001, @result);
+SELECT @result;
+```
+
+
+
+### 数据库-2
+
+```sql
+#1  插入记录
+INSERT INTO t_student()
+VALUES(DEFAULT, '赵十', '男', 17, '10006');
+
+#2 添加字段
+ALTER TABLE t_student ADD notes VARCHAR(255);
+
+#3 创建表
+CREATE TABLE t_teacher(
+	tid CHAR(10) PRIMARY KEY,
+	tname VARCHAR(20) NOT NULL,
+	sex CHAR(2),
+	age INT(2),
+	subject VARCHAR(20),
+	salary DECIMAL(10, 2)
+);
+
+#4 设置薪资默认值
+#ALTER TABLE 表名 ALTER 字段名 SET DEFAULT 默认值;
+ALTER TABLE t_teacher ALTER salary SET DEFAULT 5000;
+
+#5 插入记录
+INSERT INTO t_teacher()
+VALUES('t0001', '王老师', '男', 42, '数学', 6000);
+
+#6 数据更新
+UPDATE t_class c
+SET c.address = '四层'
+WHERE c.cname = '高三2班';
+
+#7 tj11 条件查询
+SELECT *
+FROM t_student s
+WHERE s.sex = '男';
+
+#8 视图
+CREATE VIEW v_class AS
+SELECT c.cname, COUNT(IF(s.sex = '男', TRUE, NULL)), COUNT(IF(s.sex = '女', TRUE, NULL))
+FROM t_student s, t_class c
+WHERE s.cid = c.cid
+GROUP BY c.cid;
+```
+