edx sql course

Label:Name Kecheng FenshuZhang San language 81Zhang San Mathematics 75John Doe Language 76John Doe Mathematics 90Harry Language 81Harry Mathematics 100Harry English 90 Method One: 　　ideas: If you can get a table, by the student's name, language scores, math scores, English scores of the table, the rest is in the where conditions to filter and can get the desired results. 　　specific measures: through the self-linking method, with "name" as the connection condition, since the connection three time

the cache are output to a file;Spool off means that the cache is closed and the file is saved on its own initiative; [Email protected] ~]$ Sqlplus/as SYSDBA Sql*plus:release 10.2.0.1.0-production on Wed June 18 13:52:25 2014 Copyright (c) 1982, 2005, Oracle. All rights reserved. Connected to:Oracle Database 10g Enterprise Edition Release 10.2.0.1.0-productionWith the partitioning, OLAP and Data Mining options [Email Protected]>spool/home/oracl

); insert INTO Employee (Id,name) Span class= "Hljs-keyword" >values (03, ' Rose '); You've noticed that some data needs to be enclosed in single quotes, such as the names of Tom, Jack, and Rose, because their data types are char type. In addition, Varchar,text,date,time,enum and other types of data also require single-quote decoration, while int,float,double and so on are not required.The first statement is a bit more than the second: (Id,name,phone) This parenthesis is the data to be added

The only reason for backupThe only reason for the backup is that we can restore when I first became a SQL Server database administrator, as long as the backup work can run successfully, I feel that everything is fine. I'll look at the SQL Server Agent to make sure those jobs are running, and that's it.I think as long as the disaster occurred, I just need to do a recovery. How hard can this be? Theoretically

13 Tuesday course 2018.01.15 mysql user management, common SQL statements, mysql database backup and recovery, 13.4 mysql user management By default, mysql has a root user, but the root directory permission is too high, which is dangerous. Therefore, you need to create a new user and grant it the corresponding permissions. User Creation Method Grant indicates authorization. all indicates all permissions.

,state)User gas Consumption chart: Gas_consume (uno,time,gid,num,state)Employee Information Sheet: Employee (WNO,PASSWD)Permission table: Rights (Rightid,comment,function)Employee Permissions Table: Staffrignt (Wno,rightid)Analysis: Initial status information is automatically generated in the energy consumption record when the user registers The Permissions table design contains: Permission number, description and function, when adding permissions, only need to add a row, employees

I. A database comprising four tables: Student table (Student), course Schedule (Course), score table (score) and teacher Information sheet (Teacher). The structure of the four tables, as shown in table 1-1 (i) to table (iv), is shown in table 1-2 table (i) ~ table (iv). Create four tables with SQL statements and complete related topics.Table 1-1 table Structure o

Department table), the insert succeeds: 7, non-null constraintsA non-null constraint (NOT NULL), which can be understood by a name, is a non-null constrained column that must not be empty when inserting a value. Violations of non-null constraints in MySQL, will not error, there will only be warnings, such as the following statement: INSERT INTO employee(id,name,salary,phone,in_dpt) VALUES(03,‘Jim‘,3400,119119,‘dpt2‘); #INSERT成功 age为空，因为没有非空约束，表中显示NULL INSERT INTO employee(id,name,age,phone,in_

, data has become an important resource and the development of new "energy", database technology has been applied to all walks of life and various aspects of the actual business data management. In the modern information society, all the business and application systems related to data information need the support of database technology. This course is a major public foundation course for computer majors, e

new empty database testusing the command: mysql -u root #因为在上一步已经退出了MySQL，现在需要重新登录 CREATE DATABASE test; #新建一个名为test的数据库 Again Ctrl + Z exit MySQL, then enter the statement to restore, the bak.sql just backed up to the test database: test We enter a command to view the table of the Tset database to verify the success of the recovery: mysql -u root #因为在上一步已经退出了MySQL，现在需要重新登录 use test #连接数据库test SHOW TABLES; #查看test数据库的表 You can see 4 tables and a

the table (1) Modify a value in the tableMost of the time we need to make changes not the entire database or the entire table, but one or more of the data in the table, which requires us to use this command to achieve precise modification:UPDATE 表名字 SET 列1=值1,列2=值2 WHERE 条件;For example, we want to change Tom's age to 21,salary to 3000: Note: Be sure to have a where condition, or there will be consequences you don't want to see (2) Delete a row of recordsDeleting a row of data in a