Example tutorial on processing special sql statements in mysql
The following editor will bring you a summary of the special processing statements of mysql's sql statements (must read). The editor thinks it’s pretty good, so I’ll share it with you now and give it as a reference. Let’s follow the editor and take a look.
1. Update the entire table. If the value of a column in a row of data is empty, then let it and another The values of a column of fields are equal
UPDATE ot_tgbz set update_day=if(update_day is null,date,update_day);
2,Update the entire table, if a field is greater than 2, then update them all to 2;
UPDATE ot_user set xingyun_num=if(xingyun_num > 2,2,xingyun_num);
3, Replace all URLs containing http://www.jb51.net/ in the thumb field in the shop_goods table with empty ones.
update shop_goods set thumb= replace (thumb,'http://www.jb51.net/','') where thumb like '%http://www.jb51.net/%';
4、sql statement multi-field wherequery
$map= " CAST(
`UE_account` AS CHAR CHARACTER
SET utf8
) LIKE '%$data%'
OR CAST(
`UE_accName` AS CHAR CHARACTER
SET utf8
) LIKE '%$data%'
OR CAST(
`UE_truename` AS CHAR CHARACTER
SET utf8
) LIKE '%$data%'
OR CAST(
`UE_phone` AS CHAR CHARACTER
SET utf8
) LIKE '%$data%'";[Related recommendations]
2. Detailed explanation of how to write sql statements to delete tables in different databases
3. mysql 5.7 Detailed explanation of the example of changing the database data storage location
4. Detailed explanation of the error reporting method when importing mysql big data into Navicat
5. MYSQL unlock Detailed explanation of examples of lock tables
The above is the detailed content of Example tutorial on processing special sql statements in mysql. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1384
52
MySQL: Simple Concepts for Easy Learning
Apr 10, 2025 am 09:29 AM
MySQL is an open source relational database management system. 1) Create database and tables: Use the CREATEDATABASE and CREATETABLE commands. 2) Basic operations: INSERT, UPDATE, DELETE and SELECT. 3) Advanced operations: JOIN, subquery and transaction processing. 4) Debugging skills: Check syntax, data type and permissions. 5) Optimization suggestions: Use indexes, avoid SELECT* and use transactions.
How to open phpmyadmin
Apr 10, 2025 pm 10:51 PM
You can open phpMyAdmin through the following steps: 1. Log in to the website control panel; 2. Find and click the phpMyAdmin icon; 3. Enter MySQL credentials; 4. Click "Login".
MySQL: An Introduction to the World's Most Popular Database
Apr 12, 2025 am 12:18 AM
MySQL is an open source relational database management system, mainly used to store and retrieve data quickly and reliably. Its working principle includes client requests, query resolution, execution of queries and return results. Examples of usage include creating tables, inserting and querying data, and advanced features such as JOIN operations. Common errors involve SQL syntax, data types, and permissions, and optimization suggestions include the use of indexes, optimized queries, and partitioning of tables.
Why Use MySQL? Benefits and Advantages
Apr 12, 2025 am 12:17 AM
MySQL is chosen for its performance, reliability, ease of use, and community support. 1.MySQL provides efficient data storage and retrieval functions, supporting multiple data types and advanced query operations. 2. Adopt client-server architecture and multiple storage engines to support transaction and query optimization. 3. Easy to use, supports a variety of operating systems and programming languages. 4. Have strong community support and provide rich resources and solutions.
How to use single threaded redis
Apr 10, 2025 pm 07:12 PM
Redis uses a single threaded architecture to provide high performance, simplicity, and consistency. It utilizes I/O multiplexing, event loops, non-blocking I/O, and shared memory to improve concurrency, but with limitations of concurrency limitations, single point of failure, and unsuitable for write-intensive workloads.
MySQL and SQL: Essential Skills for Developers
Apr 10, 2025 am 09:30 AM
MySQL and SQL are essential skills for developers. 1.MySQL is an open source relational database management system, and SQL is the standard language used to manage and operate databases. 2.MySQL supports multiple storage engines through efficient data storage and retrieval functions, and SQL completes complex data operations through simple statements. 3. Examples of usage include basic queries and advanced queries, such as filtering and sorting by condition. 4. Common errors include syntax errors and performance issues, which can be optimized by checking SQL statements and using EXPLAIN commands. 5. Performance optimization techniques include using indexes, avoiding full table scanning, optimizing JOIN operations and improving code readability.
MySQL's Place: Databases and Programming
Apr 13, 2025 am 12:18 AM
MySQL's position in databases and programming is very important. It is an open source relational database management system that is widely used in various application scenarios. 1) MySQL provides efficient data storage, organization and retrieval functions, supporting Web, mobile and enterprise-level systems. 2) It uses a client-server architecture, supports multiple storage engines and index optimization. 3) Basic usages include creating tables and inserting data, and advanced usages involve multi-table JOINs and complex queries. 4) Frequently asked questions such as SQL syntax errors and performance issues can be debugged through the EXPLAIN command and slow query log. 5) Performance optimization methods include rational use of indexes, optimized query and use of caches. Best practices include using transactions and PreparedStatemen
How to build a SQL database
Apr 09, 2025 pm 04:24 PM
Building an SQL database involves 10 steps: selecting DBMS; installing DBMS; creating a database; creating a table; inserting data; retrieving data; updating data; deleting data; managing users; backing up the database.


