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1 using System; 2 using System.IO; 3 4 public class Program 5 { 6 public static void Main() 7 { 8 string path = @"C:\Users\user\Downloads"; 9 Console. 阅读全文
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1 using System; 2 3 public class Program 4 { 5 public static void Main() 6 { 7 object o ="3"; 8 int j = 4; 9 10 if(o is int i) 11 { 12 Console.WriteLi 阅读全文
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1 using System; 2 3 public class Program 4 { 5 public static string CardinalToOrdinal(int number) 6 { 7 switch(number) 8 { 9 case 11: 10 case 12: 11 c 阅读全文
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1.基本查询 SELECT column FROM table; 2.有条件查询 SELECT common_name ,scientific_name FROM birds WHERE family_id =103 LIMIT 3; 3.结果排序 -- ORDER BY 默认升序(ASC), 逆序 阅读全文
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1.语法 -- 基本语法 INSERT INTO table [(column,...)] VALUES (value,...),(...),...; -- Example INSERT INTO books VALUES('The Big Sleep','Raymond Chandler','19 阅读全文
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创建数据库 -- Firsr way CREATE DATABASE database_name; -- Second way CREATE SCHEMA database_name; 2.创建表 CREATE TABLE birds( bird_id INT AUTO_INCREMENT PRIM 阅读全文