RGBMarco的博客

\encoding utf-8;/*beging:创建需要学习的数据库study开始postgresql的学习*/CREATE DATABASE study;\c study;\encoding utf-8;/*next:创建新表weathercity temp_lo temp_hi preciptation*/CREATE TABLE w...

\c study;/*begin:视图对于所作的频繁操作,创建视图比较方便*/--创建视图CREATE VIEW myview AS SELECT city, temp_lo, temp_hi, prcp, date, location FROM weather, cities WHERE city = name;--使用视图SELECT * FROM myview;/*n...

–1.窗口函数进阶/*CREATE DATABASE Study;\c Study;*/–学习准备 /* CREATE TABLE Student ( Number numeric(8,0) PRIMARY KEY NOT NULL, Name varchar(10) NOT NULL, Sex char(4) ...

--表的完整性--缺省值--若表字段未明确声明缺省值,则默认缺省值为NULL--缺省值在表定义中类型后定义的CREATE TABLE Products ( product_no integer, name text, price numeric DEFAULT 9.99);DROP TABLE Products;--序列对象暂时还未创建/*--next...

--修改表/*CREATE TABLE Student ( Number numeric(8,0) PRIMARY KEY, Age integer NOT NULL);--增加字段ALTER TABLE Student ADD COLUMN Sex varchar(10) DEFAULT '男' CHECK(Sex IN('男','女'));...