MySQL

Mysql function instance-new user on Statistics Day SQL code CREATE FUNCTION 'statics _ user_new '() RETURNS int (11) comment' statistics newly added users 'in in # Routine body goes here... DECLARE stopFlag int default 0; DECLARE _ shop_id VARCHAR (1

Mysql function instance-monthly logon user count, which is only a memo. Java code create function statics_user_login_month () RETURNS int (11) COMMENT 'monthly user count \ r \ n' BEGIN # Routine body goes here... DECLARE stopFlag int default 0;

MySQL database regularly backs up Shell scripts and backs up them to other machines. This is a simple MySQL database backup shell script, applicable to mysql database backup on a single Linux server or VPS, the working principle is to use mysql

For tables with the same fields in mysql (used by union), cross-table statistics are required when multiple tables are maintained and used, after query, you can use the union and union all statements to implement union and union all. They combine

Mysql join optimization 1. multi-Table connection type 1. cartesian products (cross join) can be considered as cross join in MySQL, or CROSS is omitted, or ',' such: SELECT * FROM table1 cross join table2 SELECT * FROM table1 JOIN table2 SELECT *

Mysql service cannot be started. mysql was installed in windows yesterday and cannot be started after the service is installed. Solution: 1. run "mysqld -- console" in the directory where mysqld.exe is located. At this time, the console displays a

There are some differences between the two-master auto-growth conflicts in Mysql and the two-master-slave replication, because multiple masters can have write permissions on the server, so the problems that arise from the design to the auto-growth

The role of ibdata in mysql Innodb and the separation of ibdata In the mysql INNODB data state is used to store file data, while the table files in the folder of the database name are only structured. Be careful, you must be careful not to delete it.

Mysql numeric data type MySQL numeric data types can be roughly divided into two categories, one is an integer, the other is a floating point or decimal. Many different subtypes are available for each of these classes. Each subtype supports data of

You don't have to worry about how to increase the speed of database update .. See the following SQL statement. [Java] String SQL = "update cats set name_alias = '" + rs. getString (1) + "'where name = '" + rs. getString (1) + "'";  If the data

Import mysql Data to infobright 1 and create a table in mysql: create table t_mis( uid mediumint not null, cid smallint not null, rating tinyint not null)engine=MyISAM;  Insert data: insert into t_mis(uid,cid,rating) values('70000','360

Importing txt data to infobright does not support insert, so data can only be imported through load. However, infobright has strict requirements on the txt format. If the format is incorrect, data cannot be imported. Let's not talk about it. import

Mysql does not support the select into solution. Insert into newTableName (column1, column2) select * from partition INTO 'aw _ Region' (tenantId, sub_product_name, call_type, call_date, expire_date, username, customer_type, start_date, end_date,

High Availability of MySQL Cluster-1 using mysql cluster can achieve high reliability of 99.999. In this chapter, we mainly introduce some basic concepts: Network Partitioning in a mysql Cluster, if a network problem occurs between several nodes,

MySQL update Error Code: 1093 and Error Code: 1175 solution MySQLSQLError Code: 1093. you can't specify target table 'ws _ product' for update in FROM clause, which is caused by the subquery added to the where condition when the update or delete

By default, mysql cannot correctly display Chinese characters. Enter the mysql command: show variables like 'character_set_%';  View Character Set settings +--------------------------+----------------------------+| Variable_name |

Note: The name of a stored procedure in mysql must be enclosed by brackets, even if there is no parameter transfer for the stored procedure. 1. Basic Syntax: Create procedure sp_name () begin ...... end modify the command Terminator delimiter $

The commonly used mysql slowquery log analysis tool has a good article about mysql optimization, which is nothing more than starting with hardware and SQL statements. Of course, the most important thing here is SQL statements, therefore, we need to

Principle of synchronization latency of a MYSQL master1. Principle of master-slave synchronization latency in MySQL databases. To talk about the delay principle, we must start with the mysql database master-slave replication principle. mysql

Set global log_bin_trust_function_creators = 1; SET FOREIGN_KEY_CHECKS = 0; -- retrieve Function structure for getPY -- revoke drop function if exists 'getpy'; DELIMITER ;; create definer = 'root' @ '%' FUNCTION 'getpy' (in_string VARCHAR (65534)