MySQL

MySql official manual Study Notes 1-MySql easy to use this is some of the notes I made when studying MySql 5.1. I hope to understand what I learned, it would be even more surprising to help you learn MySql in the same way. To connect to or

When the mysql insert update statement runs this statement, it automatically determines whether there is a duplicate primary key in the database with the record you want to insert. If yes, it is updated. If not, the insert format is as follows:

The correct method for MYSQL to view and modify the storage engine used by the table is: show table status from db_name where name = 'table _ name '; + ------ + -------- + --------- + ------------ + ------ + ---------------- + ------------- +

In windows, what should I do if I forget my mysql password? I will give a case and explanation! Solve the problem! The actual operations in Windows are as follows: 1. Disable running MySQL. 2. Open the DOS window and go to the mysql \ bin directory.

In Mysql, to determine whether a point falls within a polygon and about geospatial data, you often need to process the associations between the two spatial data. There are many ways to handle this by writing program algorithms or calling the

How to add an index for MYSQL 1. add primary key (primary key index) www.2cto.com mysql> alter table 'table _ name' add primary key ('column ') 2. add unique (UNIQUE index) mysql> alter table 'table _ name' add unique ('column ') 3. add index

The group_concat function and connection field in MySQL. The complete syntax of the group_concat function in MySQL is as follows: group_concat ([DISTINCT] field to be connected [Order by asc/DESC sorting field] [Separator 'delimiter']) basic query

Mysql optimized index -- when Using filesort uses Explain to analyze SQL statements, it is often found that Using filesort appears in some statements in the Extra column. According to the description in the mysql official documentation: www.2cto.com

The impact of null value in mysql during expression computation in mysql when any type of field and null value are calculated, the result is still null value www.2cto.com For example, 1 + null = null 'A' + null = null sometimes the null value must

Create a new user in mysql. First, log on with the root permission to create the user SQL code create user username identified by 'Password '; www.2cto.com this user can log on to the database in any place. The SQL code create user username @ ip

Mysql Modify/revoke permissions mysql for security, by default, can only log on locally, disable the remote login permission, if you need to log on remotely, perform the following configuration: www.2cto.com (1) log on to mysql: [password can be

We recommend that you use the auto-increment ID that is not related to the business as the primary key for Innodb without special requirements.We recommend that you use auto-incrementing IDs that are not related to the business as the primary key

MySQL deadlock causes query resolution. Recently, when the database is being maintained, the data cannot be stored into the database during data parsing. The reason is that MySQL transactions have deadlocked. I restarted MySQL several times before.

Mysql permission management: a non-db administrator creates mysql and installs mysql. When a database is created, several accounts are required for permission management. The following is a summary of the four accounts. Www.2cto.com 1. root Account,

Remedy after mysql forgets the root password. After mysql is installed, if you want to run/usr/bin/mysqlsecureinstallation for security setting, you are prompted to enter the root password, if you do not know the root password, we can go to/etc/my.

Mysql for cainiao: adding, modifying, and deleting ColumnsTest data:   I. Column addition:1. alter table name column DeclarationThe added columns are at the end of the table by default.   2. You can use "after" to specify which columns are behind

Differences between after and before in triggersAfter is triggered after data is added, deleted, and modified.The statement that is triggered is later than the monitor's add, delete, and modify operations.Before is triggered first, and then added,

Usage of standard SQL statements in mysql> set cascade update or delete: add constraint on delete cascade;> link query: syntax format: from TABLE1 join_type TABLE2 [on join_condition] [where query_condition] join_condition: Connection condition;

Exception in thread "main" java. SQL .. A java + mysql program has been written on the local machine, but when it is transplanted to other machines, an error is always reported when the database is inserted, as shown in [java] Exception in thread

The Java code set @ field_list = ''syslog _ id' int (11) not null AUTO_INCREMENT, 'create _ user' varchar (32) default null, primary key ('syslog _ id') '; call branch_table ('test', @ field_list, 4, 2 ); java code drop procedure if exists 'Branch _