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explain command By adding the explain keyword before the select statement, MySQL will set a flag on the query, so that when the query is executed, the execution plan information will be returned instead of executing the SQL. The explain command can obtain information about how MySQL executes SELECT statements to view the execution plan of the ...

1. Summary One of the hardest things for many beginners learning MySQL before learning SQL Server is that there are subtle differences in their grammar, such as the absence of keywords such as modify and change in SQL Server, or every statement in MySQL. At the end, SQL Server uses the go keyword to indicate the end of a batch statement, a ...

background When the business party migrates, the total data size is only more than 300 M, but the MySQL server prompts that the packet exceeds max_allowed_packet, but there is no problem with 10G pressure test data during test migration? The final solution to the problem is very simple, adjust the appropriate max_ allowed_ The size of ...

For the real problems of large factories, it is necessary to have a good understanding of the problems. The problems with similar sources and actual projects are the most important to exercise thinking ability and programming skills. Part1: a short audio and video SQL1 average completion rate of each video Level: simple Title: User video inter ...

catalogue 1.Mysql function classification 2. Common mathematical functions 3. String function (key) 4. Date and time functions 5. Process control function 6. Other functions 1.Mysql function classification (1) Single line function characteristic: A single line function operates on a single lineEach row returns a result. The returned ...

brief introduction What does MySQL master-slave replication do 1.MySQL master-slave replication does not affect the normal operation of the business during the table locking process. The master database is responsible for writing and the slave database is responsible for reading. In this way, the master database can also lock the table and ...

catalogue 1. Grouping function 2.HAVING clause 3.SELECT statement execution process 4. Sub query 1. Grouping function (1) Why use grouping functions: Grouping function is to operate on the set of data rows and give a result by group. This result can be output directly or used as judgment conditions. (2) Difference between grouping func ...

1, Introduction to Zabbix monitoring 1.1 Zabbix monitoring architecture In order to prevent Zabbix single point of failure, Zabbix high availability is made. If the company cluster is not large, a single machine can be used;If there are too many agents, you need a Proxy to reduce the pressure on Zabbix;The data is stored in the databa ...

Install MySQL using yum or up2date for Linux There are many ways to deploy MySQL database, including yum installation, RPM installation and compilation installation. Each installation method has its own advantages, so enterprises usually use rpm and binary installation. Download address of database official website: https://downloads.mysq ...

What scenarios do you use Spring's @ Transactional annotation to control transactions that do not take effect? I don't know if my friends have such an experience. When they are happy to write business code, suddenly the transaction in a method seems to fail. Then, when debug ging tracks the code, it is found that after the execution of the fir ...