丰满饥渴老女人hd,法国性xxxx精品hd

Article Tags

All
web3.0
- All
- NoSQL database
- Memcached
- cloudera
- memcache
Backend Development
- All
- PHP Tutorial
- Python Tutorial
- Golang
- XML/RSS Tutorial
- C#.Net Tutorial
- C++
- NoSQL database
- Memcached
- cloudera
- memcache
Web Front-end
Database
- All
- Mysql Tutorial
- navicat
- SQL
- Redis
- phpMyAdmin
- Oracle
- MongoDB
- NoSQL database
- Memcached
- cloudera
- memcache
Operation and Maintenance
- All
- Mac OS
- Linux Operation and Maintenance
- Apache
- Nginx
- CentOS
- Docker
- NoSQL database
- Memcached
- cloudera
- memcache
Development Tools
- All
- VSCode
- sublime
- notepad
- git
- composer
- NoSQL database
- Memcached
- cloudera
- memcache
PHP Framework
- All
- Laravel
- YII
- NoSQL database
- Memcached
- cloudera
- memcache
Common Problem
- All
- NoSQL database
- Memcached
- cloudera
- memcache
Other
- All
- IIS
- SEO
- Premiere
- NoSQL database
- Memcached
- cloudera
- memcache
Tech
- All
- AI
- It Industry
- NoSQL database
- Memcached
- cloudera
- memcache
CMS Tutorial
- All
- WordPress
- NoSQL database
- Memcached
- cloudera
- memcache
Java
- All
- javaTutorial
- NoSQL database
- Memcached
- cloudera
- memcache
System Tutorial
- All
- Windows Series
- LINUX
- MAC
- NoSQL database
- Memcached
- cloudera
- memcache
Computer Tutorials
Hardware Tutorial
Mobile Tutorial
- All
- Mobile News
- iPhone
- Android Phone
- NoSQL database
- Memcached
- cloudera
- memcache
Software Tutorial
Mobile Game Tutorial

Home

Technical Articles

Database

Mysql Tutorial

What is the FIND_IN_SET() function in MySQL?

FIND_IN_SET()returnsthe1-basedpositionofastringinacomma-separatedlist,or0ifnotfound,andisusefulforsearchingdenormalizeddata;however,itrequiresexactmatches,iscase-insensitivebydefault,performspoorlyonlargetablesduetolackofindexsupport,andshouldbeavoid

Aug 18, 2025 am 07:57 AM

How to work with spatial data in MySQL

To use spatial data in MySQL, you need to make sure to use the InnoDB storage engine that supports spatial indexing and enable the spatial function; 1. When creating a table, specify space types such as POINT and SRID4326, and add SPATIALINDEX to improve query performance; 2. Use OGC standard spatial data types such as POINT, LINESTRING, POLYGON, and insert data through ST_PointFromText, pay attention to the coordinate order of longitude and latitude behind; 3. Use ST_Distance_Sphere to calculate the earth's surface distance (unit in meters), use ST_Contains to determine whether the points are in the polygon, or use ORDERBY distance through ORDERBY distance; 3. Use ST_Distance_Sphere to calculate the earth's surface distance (unit in meters), use ST_Contains to determine whether the points are in the polygon, or use ORDERBY distance

Aug 18, 2025 am 07:35 AM

mysql spatial data

How to delete a database in MySQL?

To delete the MySQL database, use the DROPDATABASE statement. This operation will permanently delete the database and all data and must be executed with caution. The basic syntax is DROPDATABASEdatabase_name, such as DROPDATABASEtest_db; if you are not sure whether the database exists, you should use DROPDATABASEIFEXISTSdatabase_name to avoid errors, such as DROPDATABASEIFEXISTSold_project; this operation is irreversible and requires DROP permissions. In the production environment, you should first confirm the database name, back up important data, and pass SHOWDATABA after deletion.

Aug 18, 2025 am 07:06 AM

How to format dates in MySQL

Date formatting in MySQL is implemented through the DATE_FORMAT() function, which uses formatting symbols to customize the date display method. The basic syntax is DATE_FORMAT(date,format); common formatting characters include: %Y (4-bit year), %m (two-digit month), %d (two-digit date), %M (full month name), %b (abbreviated month name), %H (24-hour hours), %i (minutes), %p (AM/PM), etc.; for example, format "2025-03-1514:35:45" to "March15,2025" with '%M%d,%Y', and convert it to "15-Mar-202502:35PM" with '%d-%

Aug 18, 2025 am 06:25 AM

Optimizing MySQL for Big Data Integration

Using the correct storage engine, optimized pattern design, adjusting configuration parameters and continuous monitoring can improve the performance of MySQL processing big data integration. 1. Priority is given to InnoDB that supports transaction and row-level locks; 2. Reasonably design the pattern according to the access mode, moderately anti-standardize and use the index reasonably; 3. Adjust configuration parameters such as buffer pool size, log file size and connection restrictions; 4. Regularly use EXPLAIN, slow query log and other tools to monitor performance and optimize query and lock contention.

Aug 18, 2025 am 05:25 AM

How to store and query IP addresses in MySQL

Use VARBINARY(16) or BIGINT to store IP addresses, 1. Use INTUNSIGNED to pair with INET_ATON()/INET_NTOA() on IPv4, 2. Use VARBINARY(16) to pair with INET6_ATON()/INET6_NTOA() when IPv4/IPv6 is supported at the same time, 3. Avoid using VARCHAR, 4. Create indexes of IP columns to improve query performance, 5. Use binary operations to achieve subnet matching, 6. Normalize IP input at the application layer or through triggers, thereby ensuring efficient storage and query.

Aug 18, 2025 am 03:01 AM

How to use the ORDER BY clause in MySQL

ORDERBY is used to sort the query results in columns, in order of ascending by default, and can specify ASC or DESC; 1. Single-column sort: For example, ORDERBYsalaryDESC is descending by salary; 2. Multi-column sort: For example, ORDERBYdepartmentASC, salaryDESC is first ascending by department, and then descending by salary; 3. Sort by column position: For example, ORDERBY2DESC is descending by second column, but it is not recommended; 4. Process NULL value: NULL is ranked first in ascending by default, and ORDERBYcommissionISNULL and commissionASC can be used to sort NULL later; 5. Sorting strings is affected by character sets, and COLLATE can be used to specify the area.

Aug 18, 2025 am 01:54 AM

mysql order by

What is the difference between NOW() and CURRENT_TIMESTAMP in MySQL?

NOW() and CURRENT_TIMESTAMP return the same result in a SELECT query, but only CURRENT_TIMESTAMP is available for default values and automatic updates in the table definition, and CURRENT_TIMESTAMP complies with SQL standards and supports unbranched syntax, so CURRENT_TIMESTAMP must be used in DDL to avoid errors.

Aug 18, 2025 am 01:35 AM

How to work with JSON data in MySQL?

Use MySQL to process JSON data to directly store, query and operate semi-structured data in relational databases. Since version 5.7, JSON types are supported; columns are defined through JSON data types and legal JSON values are inserted, MySQL will automatically verify the syntax; data can be extracted using JSON_EXTRACT() or -> (returns quoted strings) and ->> (returns unquoted values), such as profile->> "$.city" to obtain city names; support filtering JSON values through WHERE clauses, and it is recommended to use generated columns and indexes to improve performance, such as ADDcityVARCHAR(50)GENERA

Aug 17, 2025 am 11:21 AM

mysql json

What are ACID properties in MySQL transactions?

ACIDpropertiesinMySQLtransactionsareAtomicity,Consistency,Isolation,andDurability,whichtogetherensurereliableandconsistentdatabaseoperations.Atomicityguaranteesthatalloperationswithinatransactionaretreatedasasingleunit,eitherfullycompletedorfullyroll

Aug 17, 2025 am 10:52 AM

What are the Different Types of Joins in MySQL and When to Use Them?

INNERJOINretrievesonlymatchingrowsfrombothtables,usedwhenyouneeddatathatexistsinbothtables;2.LEFTJOINreturnsallrowsfromthelefttableandmatchedrowsfromtheright,withNULLsfornon-matches,idealforincludingallprimaryrecords;3.RIGHTJOINreturnsallrowsfromther

Aug 17, 2025 am 10:07 AM

What is the difference between REAL, DOUBLE, and FLOAT in MySQL?

REALisasynonymforDOUBLEbydefault,butcanactasFLOATifREAL_AS_FLOATSQLmodeisenabled;FLOATuses4byteswith~7-digitprecisionforsingle-precisionvalues,DOUBLEuses8byteswith~15–17-digitprecisionfordouble-precisionvalues,andREAL’sbehaviordependsonSQLmode,making

Aug 17, 2025 am 09:53 AM

mysql type of data

How to handle errors in MySQL stored procedures

UseDECLARECONTINUEorDECLAREEXITHANDLERtospecifyerrorhandlingbehavior,whereCONTINUEallowsexecutiontoproceedafterhandlingtheerror,andEXITstopsexecutionofthecurrentblock;2.HandleerrorsusingSQLSTATEvalues(e.g.,'23000'forconstraintviolations),MySQLerrorco

Aug 17, 2025 am 06:50 AM

mysql stored procedure

How to create a database in MySQL

To create a database using the MySQL command line, you must first log in and execute CREATEDATABASEdatabase_name; for example, CREATEDATABASEmy_first_db; 2. You can verify that the database was created successfully through SHOWDATABASES, and then use USEmy_first_db; select the database; 3. It is recommended to set character sets and collation: CREATEDATABASEmy_first_dbCHARACTERSETutf8mb4COLLATEutf8mb4_unicode_ci; 4. To create a database in phpMyAdmin, you must open the web interface and enter the data

Aug 17, 2025 am 06:33 AM