摘要： 首先创建主表create table Master( VoteId int primary key,VoteTitle varchar(30) not null, VoteSum int default 0)insert into Master values(1,'选取班长',0)insert into Master values(2,'选取学习委员',0)insert into Master v... 阅读全文

摘要： ALTER TABLE table { [ ALTER COLUMN column_name { new_data_type [ ( precision [ , scale ] ) ] [ COLLATE < collation_name > ] [ NULL | NOT NULL ] | {ADD | DROP } ROWGUIDCOL } ] | ADD { [ < colu... 阅读全文

摘要： create database TestDataBase --首先创建一个库use TestDataBase--使用此库create table PersonLike--创建表( id int primary key, --主键like varchar(100) not null --非空--插入三条记录insert into PersonLike values(1,'钓鱼')insert int... 阅读全文

摘要： 1.字符型：sql-92: char,varcharmysql:char,varchar & & binary,varbinarymssql: char,varchar & nchar,nvarchar & binary,varbinaryoracle: char, varchar2(varchar), raw, nchar, nvarchar2, 注：varcha... 阅读全文