MySQL入門基礎1
一、資料庫的增刪查
建立資料庫:
CREATE DATABASE 資料庫名稱;
示例:CREATE DATABASE member;
檢視資料庫:
SHOW DATABASES;
SHOW DATABASE資料庫名稱;
刪除資料庫:
DROP DATABASE 資料庫名稱;
二、表的增刪改查:
建立表:
CREATE TABLE 表名稱(
欄位名1 欄位型別 PRIMARY KEY AUTO_INCREMEMT,
欄位名2 欄位型別,
欄位名3 欄位型別,
...
)DEFAULT CHARSET=utf8;
示例:
DROP TABLE IF EXISTS boys;
CREATE TABLE boys(
boyNum VARCHAR(20),
matchNum INT(10)
);
修改表:
1、修改表字段
-- 新增表字段
ALTER TABLE member ADD regTime TIMESTAMP DEFAULT CURRENT_TIMESTAMP();
新增欄位到指定末尾
ALTER TABLE member ADD type TINYINT DEFAULT 1 AFTER mobilephone;
--新增多列
ALTER TABLE member ADD regTime TIMESTAMP DEFAULT CURRENT_TIMESTAMP(),ADD type TINYINT DEFAULT 1 AFTER mobilephone;
--刪除多列
ALTER TABLE member DROP type;
ALTER TABLE member DROP type,DROP regTime;
--刪除並新增
ALTER TABLE member DROP regTime,ADD type TINYINT DEFAULT 1 AFTER mobilephone;
--修改表字段
ALTER TABLE member MODIFY type INT UNSIGNED DEFAULT 2;
2、修改列定義和表名
-- 修改列定義
ALTER TABLE member MODIFY type TINYINT UNSIGNED NOT NULL;
ALTER TABLE member MODIFY type SMALLINT UNSIGNED NOT NULL FIRST;
-- 修改預設值
ALTER TABLE member MODIFY type INT UNSIGNED DEFAULT 2;
ALTER TABLE member ALTER type SET DEFAULT NULL;
ALTER TABLE member ALTER type DROP DEFAULT;
-- 修改列名
ALTER TABLE member CHANGE COLUMN regTime crateTime TIMESTAMP;;
-- 修改表名
ALTER TABLE member RENAME student;
RENAME TABLE student TO member;
刪除表:
DROP TABLE 表名;
查詢表:
SHOW TABLES;