tamagotchi 1990

as the following, you will not use this index: SELECT * FROM mytbl WHERE YEAR(date_col) This expression does not compare 1990 to the indexed column, and it compares 1990 to the value computed by the data column, and each data row must compute the value. As a result, the index on the date_col is not used because executing such a query requires a full table scan. How to solve this problem? You only need t

Add sex int (modify table, add column)--Modify Table Delete columnALTER TABLE student drop column sex--Delete the entire tableDROP TABLE Student--inserting data into a table (insert only one piece of data at a time)INSERT into student values (1, ' Zhang San ', 1990-09-22)Querying all data in a tableSelect *from Student--Modify dataUpdate student Set birthday = ' 1990-09-09 '--Delete dataDelete from student

Tags: size nbsp ges cal img COM Art COMPUTE tornado(-1) write in front article refer to Http://blog.sina.com.cn/willcaty. For one of the exercises to come up with two other answers, I hope users give more answers. (0) basic data Student Table +-----+--------+------+-------+------------+--------------+ | ID | name | sex | Birth | Department | Address | +-----+--------+------+-------+------------+--------------+ | 901 | Zhang Lu | male | 1985 | Computer Systems | Haidian District, Beijing | |

used for querying. EXPLAIN SELECT * from book WHERE year_publication = 1990\g; Explanation: Although there is no data in the table, there is a explain keyword that is used to see if the index is being used and to output information about the index it is using. 　　　　　　　　　　　　　　　　　　　　　　　 The id:select identifier. This is the query sequence number for SELECT, which is a statement in which the select occurs several times. In the second statement, select ha

score tableMysql> DESC score;+--------+-------------+------+-----+---------+-------+| Field | Type | Null | Key | Default | Extra |+--------+-------------+------+-----+---------+-------+| ID | Int (10) | NO | PRI | NULL || stu_id | varchar (20) | YES | | NULL | || C_name | varchar (20) | YES | | NULL | || Grade | Int (10) | YES | NULL |+--------+-------------+------+-----+---------+-------+4 rows in Set (0.00 sec)Inserting data into the student tableMysql> select * from student;+----

Artop's salary to 7000 UPDATE t_user SET money=7000 WHERE username= ' Luo Cheng '; --all employees have a 500 rise in wages UPDATE t_user SET money=money+500 WHERE birthday>= ' 1990-01-01 '; --Change the name of the person with ID 2 to Li Shimin UPDATE t_user SET username= ' li Shimin ' WHERE id=2; --Delete all the records of the two methods (delete records the directory log, a location after the deleted data can also be restored, but inefficient, tr

that the Binlog log expires 4. Test Case [[Email protected]]$ mysql-uroot-p Enter Password: Welcome to the MySQL Monitor. Commands End With; or G. Your MySQL Connection ID is the server version:5.0.26-standard-log Type ' help ', ' or ' h ' for help. Type ' C ' to clear the buffer. mysql> use test; Database changed Mysql> select * from pet; +----------+--------+---------+------+------------+------------+ | name | Owner | Species | sex | Birth | Death | +----------+--------+---------+------+-----

10th-Period function#获得当前日期SELECT curdate ();#获得当前时间SELECT Curtime ();#获得当前日期和时间SELECT now (); #俩个时间间隔天数SELECT DATEDIFF (now (), ' 1994-12-09 ') Year (date) Gets the years in dateDate (date) Gets the date in dateMinute (date) Gets the minute in dateHour (DATR) gets the hour in dateAdddate (date,n) calculates date date plus n days 11 Mathematical functions Ceil (2.3) returns the smallest integer greater than or equal to the value 2.3 gets 3Floor (2.3) returns the largest integer less than or equ

| Birth | Death |+----------+-------+---------+------+------------+------------+| Claws | Gwen | Cat | m | 1994-03-17 | NULL || Bowser | Diane | Dog | m | 1989-08-31 | 1995-07-29 || Whistler | Gwen | Bird | NULL | 1997-12-09 | NULL |+----------+-------+---------+------+------------+------------+Now that if a regular expression appears anywhere in the value and its pattern matches, you don't have to put a wildcard in the two aspects of the pattern in the previous query so that it matches the ent

1. Use the shell to "12306 User name and password library-do not use Notepad to open the card will die-after decompression can be used word or ultraedit open. rar" All records genetic SQL statements, and then the SQL into the database into a upwd_12306 table. The field is defined by itself.Extension: Please analyze the formation characteristics of the password in the "12306 User name and password Library" and summarize it.2. Copy the "12306 User name and password library-do not use Notepad to op

of the support partition operation has 5.1 and 5.5 SHOW VARIABLES like '%partition% '; Display as Yes indicates that the database supports partitioning operations. (2) Create four types of partitions Range Partition: Scope partition- based on the value of the field in the table, partitioning is based on a contiguous interval given a segment. #创建teacher表 and divide the table into P1, P2, p3 three partitions based on the Birthdate field while creating the teacher table. CREATE TABLE teacher (I

gender from D Epartments A,dept_manager b,employees C where a.dept_no=b.dept_no and B.emp_no=c.emp_no order by department number;Exercise: Information about employee number, employee name (first_name+last_name), department, employee and salary of 1990 years after joining the companyCreate a new table Einfo.Mysql> CREATE TABLE Einfo (select Employees.emp_no,concat (Employees.first_name, ', Employees.last_name) as employee name, Employees.hire_date,dep

', 666, ' 15878945612 ', ' [email protected] 'INSERT into student (Studentno,sname,sex,birthday,classno,point,phone,email) VALUES (' 0823210007 ', ' Stay far ', ' Male ', ' 1988-12-7 ', ' 080501 ', 658, ' 12545678998 ', ' [email protected] 'INSERT into student (Studentno,sname,sex,birthday,classno,point,phone,email) VALUES (' 0824113307 ', ' Cui Yan ', ' Male ', ' 1988-4-8 ', ' 080601 ', 787, ' 15556845645 ', ' [email protected] 'INSERT into student (Studentno,sname,sex,birthday,classno,point,p

Label:The Paxos algorithm in distributed databaseHttp://baike.baidu.com/link?url=ChmfvtXRZQl7X1VmRU6ypsmZ4b4MbQX1pelw_VenRLnFpq7rMvYfDDmg3Rg1Aw6YyobKozdN599x2sCiJNNHV_The Paxos algorithm is Leslie Lambert (Leslie Lamport, the "La" in LaTeX, which is now in Microsoft Research), which was presented in 1990 as a consistency algorithm based on message passing. This algorithm is considered to be the most effective in similar algorithms.Chinese namePaxos al

Database statusDatabase technology was generated in the late 60, is the latest technology of data management, is an important branch of computer science.Database technology is the core and foundation of information system, its appearance has greatly promoted the infiltration of computer application to all walks of life.The scale of database construction, the size of database information and the frequency of use have become the important sign of measuring the informatization degree of a country.D