MySQL

Recently, a batch of data needs to be processed from the fields in the table in the library and then exported to a new table. However, this table has a data volume of nearly 500w. The problem with this amount of data is that it takes a long time to

# # Root user to modify their own password # The first method: Modify the mysqladmin-u root-p password "test" through the mysqladmin command will prompt you to enter the old password after the terminal type the above command, enter the password to

1. Export local database data to a local fileMysql-a service_db-h Your_host-utest-ptestMysql> SELECT * from T_apps where created> ' 2012-07-02 00:00:00 ' into outfile/tmp/apps.csv2. Export remote database data to a local fileMysql-a service_db-h

For the MySQL database garbled problem, there are two cases:1. MySQL database encoding problem (set when building the library).2. Link the URL encoding setting of the MySQL database.For the first question, the current personal discovery can only be

The Type field in the explain execution plan is divided into the following types:All INDEX RANGE REF eq_ref const,system NULLFrom left to right, performance from worst to bestType = all, full table scan, MySQL scan full table to find matching rows

Mysql> Select * fromT2;+----+---------------------+|Id|D|+----+---------------------+| 1 | -- ,- Geneva the: -: - || 3 | -- ,- to -: About: at || 4 | -- ,- to -: About: - || 6 | -- ,- to -: About: - || 7 | -- ,- to -: About: - || 8 |

Recommended Parameters: max_connections=800 key_buffer_size=512mquery_cache_size=128msort_buffer_size=64mtable_open_cache=512 Sort_buffer_size = 2MRead_buffer_size = 2MRead_rnd_buffer_size = 8MMyisam_sort_buffer_size = 64M

The DBA sends a slow query problem on the line, and SQL is as follows (omitting some of the highlights for highlighting):SELECT DISTINCT Article0_.id, etc. fields from Article_table article0_, hits_table articlehit1_ where article0_.id=articlehit1_.

2015/08/041. Install MySQL using the default yum:#yum install MySQL#yum Install Mysql-server#yum Install Mysql-devel2. Configure MySQL file permissions:#chgrp-R Mysql/var/lib/mysql#chmod-R 770/var/lib/mysql3. Start MySQL:#service mysqld Start4. Log

MySQL supports a number of data types, and choosing the right data type is critical to getting high performance. There is a simple principle in choosing to help make better choices.The simple principle:A, usually the smallest is the bestThis can

# #2015-07-25 Find the ID of the last inserted record INSERT INTO ...//// immediately after the INSERT statement select LAST_INSERT_ID ();# #2015 -07-15 Convert to date from_unixtime (addtime, '%y-%m-%d%h:%m:%s ') group_concat

SameShowThe timestamp column is displayed in the same format as the datetime column. In other words, the display width is fixed at 19 characters, and the format is Yyyy-mm-dd HH:MM:SS.DifferentRangedatetime Retrieves and displays datetime values in

"MySQL" Go MySQL development 36 2012-05-14 14:02:33Category: Linux written in the previous words:It is always after the disaster that the importance of disaster tolerance is remembered;always after the loss, just remember that there was a reminder. (

The following instructions are based on MySQL 5.5.Overview: I know that most people don't use much for MySQL cursors. In most cases, MySQL can use the "set" operation to meet the 90% requirement. MySQL cursor as a "record" operation, is a complement

MySQL creates a new user:CREATE USER username identified by ' password ';Assign all permissions to the new user:GRANT all privileges on * * to ' username ' @ ' localhost ' identified by ' password ';To modify a user's permissions, first cut back to

MySQL query, where, common functions, having201507311. How do I write query statements in MySQL?A: Consider the column as a variable, and the where behind is the EXP expression in the IF (exp).2. Which lines have been taken out?A: Which line can

Since it is the first time to install, it is not possible to determine whether you have installed the build and MySQL to rely on the plug-in, use I was as your most original installation environment.1, install the mysql5.1 dependency packageYum

When we were hired to monitor MySQL performance, people wanted us to look at the MySQL configuration and give some suggestions for improvement. Many people were surprised after the fact because we suggested that they only change a few settings, even

MySQL performance can only be achieved when query optimization, index optimization, and library table structure optimization go hand in hand.Before trying to write a quick query, it's important to be clear that the real importance is response time.

At the beginning of self-study JSP, in the course of the practice encountered a very serious problem, is the Chinese characters garbled problem, I used three days of time, collect information, finally solved the problem, now to learn something to