MySQL

Different from most databases, mysql has a storage engine. For different needs, you can select the storage engine that best suits you. How many storage engines are there in mysql, what are their advantages and disadvantages, The mysql tutorial is

Software used: MySQLMigrationTool The system prompts that the data is too large to be imported. Modify the max_allowed_packet of the my. cnf file to be greater than MB. In windows, my. cnf may not be displayed. You need to enter the address: drive

SQL union syntax and Examples SQL union allows you to query the results of two or more individuals. The consortium is different because queries are subqueries that are independent from each other. The Consortium combines these individually selected

Three methods to return the record id after inserting a record in the mysql tutorial Method 1 Id int (11) not null pri key auto_increment, name varchar (12), backup varchar (50)Now, when you want to insert a record, return its id value (only the

◆ Actively monitors MySQL access recordsMySQL contains many different log files that record customer connection, query, and server errors. Among them, the most important is the general query log, which uses time labels to record the connection and

1. Change the table. It may be that your account is not allowed to log on remotely, but only on localhost. At this time, you only need to log on to the localhost computer and change the "host" item in the "user" table in the "mysql" database

Mysql tutorial Regular Expression query and instance ^ Match the start part of the string$ Match the end part of a string$ SQL = "SELECT 'fonfo 'regexp '^ fo $' from string_find "; . Match any character (including carriage return and new line)$ SQL =

SQL multi-Table query Select distinct (. name, B. name), COUNT (Electric Appliance sales revenue + special monthly sales revenue) as monse, COUNT (Electric Appliance sales revenue + special annual sales revenue) as year FROM a, B WHERE. id = B.

Mysql Stored Procedure instance Mysql Stored Procedure instanceTechnical Points A stored procedure includes a name, a list of parameters, and a set of SQL statements that can contain many SQL statements. The following is a stored procedure

Concat Concat_ws Mysql SQL character connection function Concat Concat_ws1. Concat () function1.1 The concat function of MySQL can connect one or more strings, suchMysql> select concat ('10 ');+ -------------- +| Concat ('10') |+ -------------- +| 10

Replace usage in MySQL and insert... update usageDrop table if exists t;Create table t (id int not null auto_increment primary key, name varchar (100 ));Create unique index idx_t on t (name );Replace into t (name) values ('first'); -- Data id =

MySQL character with separator connection concat_ws and concat Mysql tutorial> select concat_ws ('-', '20160301', 123, '20160301 ');+ -------------------------------- +| Concat_ws ('-', '123', 123, '123') |+ -------------------------------- +| 123-45

Mysql database connectionClass MySQL {// Database SectionVar $ DBServer = 'localhost'; // serverVar $ DBName = ''; // Database NameVar $ DBUser = ''; // Database UserVar $ DBPass = ''; // Database PasswordVar $ OnErrorResume = 1; // the error

MySQL Database Security SolutionAccount is the simplest security measure for MySQL. Each account consists of the user name, password, and location (generally composed of the server name, IP address, or wildcard. If john logs on from server1, the

Bidirectional encryptionLet's start with the simplest encryption: two-way encryption. Here, a piece of data is encrypted by a key and can only be decrypted by the person who knows the key. MySQL has two functions to support this type of encryption:

This chapter describes the group by (aggregate) functions used for a group of numerical operations. Unless otherwise specified, the group function ignores NULL values. If you use a group function in a statement that does not contain the roup by

SQL getting started The SQL getting started tutorial is just what we learned in the learning process. Let's take a look at the mysql getting started tutorial below. Let's take a look at the tutorial. Query statement:SELECT field name FROM table name.

Primary KEY constraints of the rimary key database Database primary key constraintsThe primary key constraint uniquely identifies each record in a database table. The primary key must contain unique values. The primary key column cannot contain null

Methods and definitions: Mysql_client_encoding returns the character set of the current page Syntax: Mysql_client_encoding (connection) Link parameter: connection:Optional. Specify the MySQL connection. If not specified, the last connection

Definition and usageTheMysql_field_type() Records in the Type field returned by the function.Returns the success of the specified field of the type, or the failure of FALSE.Syntax Mysql_field_type(Data, field_offset) Parameter descriptionData :.