MySQL

Simple MySQL Tutorial Group Statistics statement Instance Code/*ID name code_id code_name is_true Score1 31, Handsome is 5.2 tickets, 32 grand, 4.3 31, Handsome is 4.4 Sheets 32 Lavish No 35 Lee 41 Handsome is 56 Lee 42 Lavish is 3 Take a look at

First, create the user: Create user creates a new MySQL account. To use create user, you must have the global Create user permission for the MySQL database or have insert permissions. For each account, create user creates a new record in the

1. Back up MySQL: Export a library to a SQL file The code is as follows Copy Code Mysqldump db_name >/home/hx/backup/name.sql-uroot-p Back up multiple libraries (using the-b parameter) The code is

One, in your computer DOS mode, at the beginning of the-> run input "cmd" Second, then go to your MySQL directory in the bin directory. Then use the source command, followed by the script file (such as the. SQL used here) Mysql>source

Advantages and disadvantages of MySQL log backups Benefits: is to revert to a point in time, or an operation SQL statement Disadvantage: A large log file is generated MySQL log recovery method in Windows 1. Open MySQL LogFind [mysqld] in the

Creating a Database Command: The code is as follows Copy Code Create DATABASE Example 1: Create a database named XHKDB The code is as follows Copy Code 1. CREATE database name;2.

Use the command mode xcopy command to save the following code as a Bak.bat file. The code is as follows Copy Code net stop MySQLxcopy D:/phpstudy/mysql/data/sql111cn/*.* d:/db_backup/%date:~0,10%//ynet start MySQL

1, find the problem of the program to join Mysql.colse () can be resolved. 2, directly modify the MySQL configuration, set time_wait time of not more than 5 seconds can modifying methods in Linux systems The code is as follows

Left JOIN syntax The code is as follows Copy Code Table_references:Table_reference [, Table_reference] ...Table_reference:Table_factor| Join_tableTable_factor:Tbl_name [[as] alias][{use| ignore| FORCE} INDEX (Key_list)]|

Explain syntax: Explain select ... from ... [Where ...] For example: Explain select * from news; Output: +--+ ————-+ ——-+ ——-+ ——————-+ ——— + ——— + ——-+ +--+ ——-+| ID | Select_type | Table | Type | Possible_keys | Key | Key_len | Ref | Rows |

Batch search: The SELECT statement is used to select data from the database. Grammar The code is as follows Copy Code SELECT column_name (s) from table_name Instance The code is as follows

This way MySQL will automatically convert all table names to lowercase characters when created and found (this option defaults to 1 in Windows and 0 in Unix). Starting with MySQL 4.0.2, this option also applies to database names. When you change

Question One 111217 23:23:57 Innodb:database is not shut down normally!Innodb:starting crash recovery.innodb:reading tablespace information from the ... ibd files ...innodb:restoring possible Half-written data pages from the

SUBSTR () is equivalent to the substring () function, and substring () is very powerful and flexible. 1. Intercept string from leftLeft (str, length) Description: Left (intercepted field, intercept length) 1, left (str,length);        Select Left

The code is as follows Copy Code Mysql> SELECT something from tableWHERE To_days (now ())-To_days (Date_col) DayOfWeek (date) Returns the week index of date (1= Sunday, 2 = Monday, ...). 7= Saturday). These index values

PHP connection MySQL Database classmysql.php Class dirver{ Connecting to a databaseLink Databasefunction Dblink ($dbhost = ' localhost ', $dbuser = ' root ', $password = ', $dbname = ', $pconnect =0) {$this->linkid[$this->line] = ($pconnect = = 1)?

Class Mysqlquery{var $sql;//sql Statement Execution resultsvar $query;//sql statementvar $num//return number of recordsvar $r;//return arrayvar $id//Return database ID numberExecute mysql_query () statementfunction query

// Database connection tutorial$ Link_id = mysql tutorial _ connect ("localhost", "root", "") or die ("connection failed ");If ($ link_id){// Select a databaseMysql_select_db ("my_test ");// The above is the connection part of the header database,

$ Errmsg = "";If (! @ Mysql_connect ("localhost", "trainee", "abc123 ")){$ Errmsg = "Cannot connect to database ";} @ Mysql_select_db ("wellho ");// First run ONLY-need to create table by un commenting this// Or with silent @ we can let it fail

Data verificationClear spacesThe trim function will clear spaces at the beginning and end of the data. Its syntax is:Trim ($ first_name );Processing of required fieldsSome fields must be entered in your database. In this way, the fields