bitsCN.com
参考表:student
多字段查询
mysql> select id,name,birth from student;
所有字段查询
mysql> select * from student;
where指定查询
mysql> select * from student where id=901;
mysql> select * from student where id>=904;
mysql> select name from student where department='计算机系';
in指定集合查询
mysql> select * from student where birth in(1988,1990);
mysql> select * from student where id in(903,906);
not in非范围查询
mysql> select * from student where birth not in(1990,1998);
between and指定范围查询
mysql> select * from student where birth between 1986 and 1988;
not between and不在指定范围的查询
mysql> select * from student where id not between 904 and 906;
like字符串匹配查询
mysql> select * from student where name like '_三';
mysql> select * from student where name like '张三';
mysql> select * from student where name like '张%';
not like不匹配查询
mysql> select * from student where name not like '张%';
null查询
mysql> select * from student where address is null;
and多条件查询
mysql> select * from student where name like '张%' and birth>1985;
mysql> select * from student where name like '张%' and birth>1985 and id like '%3';
or多条件查询
mysql> select * from student where id=905 or birth=1988;
mysql> select * from student where id=905 or birth=1988 or sex='女';
distinct查询结果不重复
mysql> select distinct sex from student;
mysql> select distinct department from student;
order by查询结果排序
mysql> select * from student order by birth;
mysql> select * from student order by birth asc;
mysql> select * from student order by birth desc;
group by分组查询
mysql> select sex,group_concat(name) from student group by sex;
mysql> select sex,count(name) from student group by sex;
正则表达式查询
mysql> select * from student where birth regexp '1988|1990';
limit限制查询结果数量
mysql> select * from student limit 2;
mysql> select * from student limit 1,3;
bitsCN.com

Mastering the method of adding MySQL users is crucial for database administrators and developers because it ensures the security and access control of the database. 1) Create a new user using the CREATEUSER command, 2) Assign permissions through the GRANT command, 3) Use FLUSHPRIVILEGES to ensure permissions take effect, 4) Regularly audit and clean user accounts to maintain performance and security.

ChooseCHARforfixed-lengthdata,VARCHARforvariable-lengthdata,andTEXTforlargetextfields.1)CHARisefficientforconsistent-lengthdatalikecodes.2)VARCHARsuitsvariable-lengthdatalikenames,balancingflexibilityandperformance.3)TEXTisidealforlargetextslikeartic

Best practices for handling string data types and indexes in MySQL include: 1) Selecting the appropriate string type, such as CHAR for fixed length, VARCHAR for variable length, and TEXT for large text; 2) Be cautious in indexing, avoid over-indexing, and create indexes for common queries; 3) Use prefix indexes and full-text indexes to optimize long string searches; 4) Regularly monitor and optimize indexes to keep indexes small and efficient. Through these methods, we can balance read and write performance and improve database efficiency.

ToaddauserremotelytoMySQL,followthesesteps:1)ConnecttoMySQLasroot,2)Createanewuserwithremoteaccess,3)Grantnecessaryprivileges,and4)Flushprivileges.BecautiousofsecurityrisksbylimitingprivilegesandaccesstospecificIPs,ensuringstrongpasswords,andmonitori

TostorestringsefficientlyinMySQL,choosetherightdatatypebasedonyourneeds:1)UseCHARforfixed-lengthstringslikecountrycodes.2)UseVARCHARforvariable-lengthstringslikenames.3)UseTEXTforlong-formtextcontent.4)UseBLOBforbinarydatalikeimages.Considerstorageov

When selecting MySQL's BLOB and TEXT data types, BLOB is suitable for storing binary data, and TEXT is suitable for storing text data. 1) BLOB is suitable for binary data such as pictures and audio, 2) TEXT is suitable for text data such as articles and comments. When choosing, data properties and performance optimization must be considered.

No,youshouldnotusetherootuserinMySQLforyourproduct.Instead,createspecificuserswithlimitedprivilegestoenhancesecurityandperformance:1)Createanewuserwithastrongpassword,2)Grantonlynecessarypermissionstothisuser,3)Regularlyreviewandupdateuserpermissions

MySQLstringdatatypesshouldbechosenbasedondatacharacteristicsandusecases:1)UseCHARforfixed-lengthstringslikecountrycodes.2)UseVARCHARforvariable-lengthstringslikenames.3)UseBINARYorVARBINARYforbinarydatalikecryptographickeys.4)UseBLOBorTEXTforlargeuns


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

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

Dreamweaver Mac version
Visual web development tools

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

SublimeText3 English version
Recommended: Win version, supports code prompts!

WebStorm Mac version
Useful JavaScript development tools
