MySQL

We know that a large MySQL table with massive records can be divided into several tables based on the primary key, time field, and condition field, or even stored on several servers.The only problem is that cross-server batch query is troublesome

DAYOFWEEK (date) Returns the index of the week of the date (1 = Sunday, 2 = Monday ,...... 7 = Saturday ). These index values correspond to the ODBC standard.Mysql> select DAYOFWEEK ('2017-02-03 ');-> 3 WEEKDAY (date)Returns the week index of date (0

MySql General paging Stored ProcedureProcess ParametersCopy codeThe Code is as follows:P_cloumns varchar (500), p_tables varchar (100), p_where varchar (4000), p_order varchar (100), p_pageindex int, p_pagesize int, out p_recordcount int, out

Test Table level;Copy codeThe Code is as follows:Create table test. level (name varchar (20 ));Insert some data; Code InitializationCopy codeThe Code is as follows:Drop procedure if exists useCursor //Create a stored procedureCopy codeThe Code is as

1> query data in addition to the first three data tables. At first, I thought of this statement. SELECT * FROM admin WHERE userid not in (SELECT userid FROM admin order by userid LIMIT 3) order by userid DESC But it will reportThis version of MySQL

Mysql updates some data in the field in the first case:Copy codeThe Code is as follows:Update tab set A = concat (substring (A, 1, 3), 'bbb '); Start from 1 character of A and add 'bbb 'to a. If the original value of A is '123aaa', it is updated to '

I have never been very familiar with the differences between the keywords in connectionstring, so it is too cumbersome to die.Let's explain some of the insights ......**************************************** ***********What is the difference between

Copy codeThe Code is as follows:Alter function [dbo]. [get_FullAge](@ Birthday datetime, @ currentDay datetime)RETURNS INTASBEGINDECLARE @ age INTSET @ age = DATEDIFF (YEAR, @ birthday, @ currentDay)If datediff (DAY, DATEADD (YEAR, @ age, @ birthday)

Difference between quotation marks and no quotation marks in Mysql Query When the database field ID is an integerSelect ID from table where ID = 1AndSelect ID from table where ID = '1'Both SQL statements are acceptable, but the first SQL statement

I recently encountered a problem of MySQL reinstallation at work. Today I will record my solution process. First of all, for some reason, I Have To uninstall mysql and then reinstall mysql. No matter how I use the control panel to uninstall and

Data is very important. I want to know this with my toes. To ensure data security, we need to regularly back up data. Here are some notes about data backup and restoration.  Data backup use the mysqldump command to back up a database mysqldump -u

The database inserts, updates, and deletes records in the table. InsertStatement to insert data UpdateStatement to update data DeleteStatement to delete dataReference Table Insert data without specifying the field name Insert field name not

Root @ DB-02 ~] # Mysql-u root-Bash: mysql: command not found Cause: by default, the system will find the command under/usr/bin. If this command is not in this directory, of course, the command cannot be found, what we need to do is map a link to

Sometimes, after reading the database, for the same result set, output on the same page may encounter multiple outputs, that is, multiple executions of mysql_fetch_array (), during the second execution, NO content is output without processing. In

One common problem is that the offset of limit is too high, such as: limit 100000,20. In this way, the system will query 100020 entries and then discard all the preceding 100000 entries. This is a very costly operation, the query is slow. Suppose

Note: in mysql, ROW_COUNT () can return the number of rows affected by the previous SQL UPDATE, DELETE, and INSERT operations. MySQL test (database version: 5.1.22 ): 1. Create a database table:Copy codeThe Code is as follows:Create table t (Id

1. Check whether logs are enabled:Show variables like 'Log _ bin '; 2. view the current Log File Name:Show master status; 3. Find out which binary log files are currently available:Mysql> show binary logs; 4. View mysql logs:Mysql-bin.000001 for

Recently, the company's MySQL architecture has been upgraded, from the original one-master-many slave to the DRBD + Heartbeat dual-master-many slave, and a new e-commerce website project is coming soon, DRBD + Heartbeat dual master and one slave are

To learn about the Mysql database and what Mysql table types are required, we will introduce you to the seven Mysql table types below, hoping to help you learn about the Mysql table types.MySQL, as the most popular free database service engine, has

Mysql stored procedures are supported from version 5. Therefore, stored procedures are generally used. Today, I will share my understanding about the Mysql stored procedure.Some simple calls and syntax rules are not described here. There are many