???? MySql will generate some logs during the running process, and now for the consistency of the master-slave data synchronization problem, as well as database recovery, database optimization, dat
Category: Database
The database is a warehouse that organizes, stores and manages data according to the data structure. It was created more than 60 years ago. With the development of information technology and the market, especially after the 1990s, data management is no longer just It is to store and manage data, and transform it into various data management methods required by users. There are many types of databases, from the simplest tables that store various data to large-scale database systems that can store massive amounts of data. They have been widely used in all aspects.
What is the fastest way to find a big table in radius mysql (latitude longitude)
Currently I have several tables with 100k rows. I am trying to find the following data.
SELECT
* , SQRT(POW(69.1 * (latitude-‘49.1044302’), 2) + POW(69.1 * (‘-122.801094’-longitude) * COS(lat
Mysql – How to choose a row with the current date time?
I tried to select only today’s records from the database table.
Currently I use
SELECT * FROM `table` WHERE (`timestamp`> DATE_SUB(now(), INTERVAL 1 DAY)); But it needs the results of t
MySQL character set
1. Character set and verification rules Character set is a set of symbols and codes, and collation is a set of rules for comparing characters in a character set. That is, the collation of the chara
MySQL case: calculation ring ratio
select a.day_num as “Serial Number”,
a.create_time as “Shelf time”,
a.clue_num as “The amount of vehicles on the shelves”,
((a.clue_num/b.clue_num)-1) as “Chain Ratio”
from
(
select cast(
MySQL index
Summary:
This is an article about MySQL, mainly introducing MySQL index
# #1. Introduction to Indexes
An index is also called a key in MySQL. It is a data structure used by the st
Is MySQL have “analysis function” in Oracle?
I am looking for analysis functions like PARTITION BY in MySQL (see docs for more information)
Does it exist ?
Update 04/2018
MySQL 8.0 now supports window functions.
I am l
Mysql: Error 1215 (HY000): Unable to add foreign key constraints
I have read about database system concepts, 6th edition, Silberschatz. I will implement the university database system shown in Chapter 2 on MySQL’s OS X. But I’m in the course of creating tables I
Mysql’s transaction
The transaction in MySQL is the smallest indivisible unit of work, and the transaction can ensure the integrity of a business
There are multiple SQL statements in a business, and these SQL st
MySQL view
What is a view? For example, if there is a basic table, user 1 can view the data and can view fields 1 and 2, and user 2 can view the fields 3 and 4, then these two users There are different views