mysql if statement in query

One: Connection query:Connection query is to connect two or more tables according to a certain condition, select the required data, the connection query query two or more tables at the same time, when there are fields representing the same meaning

MySQL Query performance optimizationThe optimization of MySQL query performance involves many aspects, including library table structure, establishing reasonable index and reasonable query. The library table structure includes how to design

This article describes how to query logs and slow query logs in MySQL. It also describes how to use the Mysqldumpslow log analysis tool that comes with MySQL. For more information, see I. query logs Query all the queries in MySQL by using "-- log [=

High Performance MySQL Reading Notes-query performance optimization, high performance mysql For high-performance database operations, it is not enough to design the optimal database table structure and build the best index. You also need to design

MySQL Format statement specificationHow do I log into your database?Example!If you are compiling the installation of the flowers, then you have to compile the installation of the directory to go, my is installed into the/usr/local/mysql database: Cd/

A basic tutorial on querying logs and slow query logs in MySQL, I. query logs Query all the queries in MySQL by using "-- log [= file_name. Because all the queries, including all the select statements, are recorded, and the size is relatively large,

Two ideas for improving Orderby statement query efficiency in mysql Analysis of two ways to improve the query efficiency of Order by statements in mysql _ MySQL Because the database records may need to be reordered. In this article, I will talk

Original works of Lin Bingwen Evankaka. Reprinted please indicate the source http: blogcsdnnetevankaka 1. user creation, permission, and deletion 1. connect to MySql Connection: mysql-h host address-u user name-p user password (note: u and root do

For high-performance database operation, it is not enough to design the optimal library table structure, and to establish the best index, but also need reasonable design query. If the query is poorly written, high performance cannot be achieved even

MySQL basic query statement learning notes, MySQL statement learning notes 1. Basic query statementSelect attribute list from Table Name and View list [where condition expression 1] [group by attribute name 1 [having condition expression 2] [order