MySQL

Mysql solves the problem of automatic disconnection of connections that have not been used for nearly eight hours, I have done some experiments on this issue. The results of the study on mysql automatic disconnection at www.2cto.com are as follows.

Database Transaction Processing exclusive lock under www.2cto.com make an experiment to verify the effect of the lock Terminal 1, first enter the transaction status and then run the following statement mysql> begin; Query OK, 0 rows affected (0.00

In linux, start the MYSQL server and configure the self-starting command/usr/local/mysql/bin/mysqld_safe -- user = mysql & note that the MYSQL installation directory www.2cto.com is configured for self-starting through vi/etc/rc. common local

The Mysql formatting date function DATE_FORMAT (date, format) formats the date or date and Time Value date based on the format string and returns the result string. Www.2cto.com DATE_FORMAT () to format the DATE or DATETIME value to obtain the

Mysql SQL Performance Optimization-order mysql's order will be affected by the amount of data selected during sorting. The more data columns, the slower the sorting. To illustrate this problem, see several examples. Low performance: select id,

In ubuntu, how to change the mysql Data Storage path is often the case when mysql data is very large. The data is stored in/var/lib/mysql by default.The space is not large enough, so we need to modify the mysql Data Storage path and put it in a

Mysql DATA import method mysqlimport 1). mysqlimport Syntax: www.2cto.com mysqlimport is located in the mysql/bin directory and is a very effective tool for mysql to load (or import) data. This is a command line tool. There are two parameters and a

In CentOS, mysqlhotcopy is used to regularly back up MySQL databases (MyISAM storage engine). mysqlhotcopy and mysqldump are compared: the former is a COPY in the sense of a fast file, and the latter is a collection of SQL statements on the database.

[Data sorting] MySQL error number meaning MySQL error number is retained for future reference. Www.2cto.com 1005: Table creation failed 1006: database creation failed 1007: database creation failed 1008: database creation failed 1009: Database

Mysql logon problems occur in Windows. when mysql is logged on, the following ERROR occurs: ERROR 1045: Access denied for user: 'root @ localhost' (Using password: YES) www.2cto.com found some solutions from the Internet and finally got a solution.

Example of a MySql stored procedure: SQL code www.2cto.com CREATE DEFINER = 'root' @ '% 'Procedure 'proc _ calculate_combo_price' (IN 'comboid' VARCHAR (36), OUT 'price' DOUBLE, OUT 'reallyprice' DOUBLE) language SQL not deterministic contains SQL

Mysql Query Optimization-Show command we can view MySQL status and variables through the show command to find the System Bottleneck: mysql> show status -- display status information (Extended show status like 'xxx') Mysql> show variables -- display

MySQL update nesting when we want to retrieve the data d1 in col1 (for example, the current blog access volume) of column id = 5 from table 1 in MySQL, when the table1 attribute p1 is updated to d1 + 1, we may think of using this SQL statement [SQL]

Mysql query data for this week, last week, this month, and last month SELECT name, submittime FROM enterprise where yearweek (date_format (submittime, '% Y-% m-% D') = YEARWEEK (now (); query the SELECT name, submittime FROM enterprise where

The first step (generally omitted) for executing SQL scripts in mysql is to enable the mysql service (which runs automatically at startup by default): control panel --> management tools --> services, find the item named mysql in it, and double-click

MYSQL obtains the auto-increment ID in four ways. select max (id) from tablename 2. the SELECT LAST_INSERT_ID () function LAST_INSERT_ID is irrelevant to table. If data is inserted to table a and then to table B, LAST_INSERT_ID changes. Max (id) is

Some maintenance tasks for mysql 5.6 partition maintenance tables and partitions are applicable to the use of SQL statements on mysql partition tables. To maintain a partition TABLE, you can use statements that support partition tables: check table,

MySql transaction trigger (Instance)1. Connection QueryUnion connects multiple select statements.Join query:When the expected results are no longer the same table, we need to use join queries.Syntax:A field in table1 join table2 on table1 = a field

Install and configure mysql SQL code in suse rpm-qa | grep mysqlCheck whether mysql has been installed, or check whether mysql has been installed in yast. I indicates that yast has been installed.> software Management --> Filters: Select RPM Groups -

Flexible handling of mysql Data Import errors is often used to resolve SQL file import to the database. It may be the restoration of the database from the mysqldump script or the database migration. Such an SQL file usually contains many statements.