search
HomeDatabaseMysql TutorialHow to convert mysql string to number

How to convert mysql string to number

Dec 02, 2021 am 11:44 AM
mysqlstringnumber

Mysql string to number method: 1. Use the "CAST(value AS type);" method to convert the string into a number; 2. Use "SELECT CAST('5.45' AS DECIMAL(9,2 ));" Convert a string to a floating point number.

How to convert mysql string to number

The operating environment of this article: Windows 7 system, Mysql version 5.7.14, Dell G3 computer.

How to convert mysql string to number?

Mysql string to number:

The simplest way is directly The 0 after the string is equivalent to directly converting the string into a numeric type. Let's take a look at the specific operations. You can see that through the 0 operation, the two strings are successfully converted into numbers, and the result after addition is obtained. the result of.

How to convert mysql string to number

Use the CAST() function, the usage method is CAST(value AS type);, you can take a look at the specific operation examples below, and check the results through the following sql statement:

SELECT CAST('5.45' AS SIGNED);

You can see that the result directly converts the string '5.45' into the number 5 because SIGNED represents an integer.

How to convert mysql string to number

If you want to convert the string '5.45' into a floating point number 5.45, you can use DECIMAL, then the sql statement will be changed to the following:

SELECT CAST ('5.45' AS DECIMAL(9,2)); , 9 and 2 represent precision and number of decimal places respectively, as shown in the figure.

How to convert mysql string to number

Use the CONVERT(value, type); method. You can see the specific operations below and view the results through the following sql statement:

SELECT CONVERT('67',SIGNED);

You can see The result is that the string '67' is directly converted into the number 67, as shown in the figure.

How to convert mysql string to number

Similarly, if you want to use the CONVERT method to convert a string with decimals into a floating point number, you can use DECIMAL directly. Take a look at the example sql below:

SELECT CONVERT('67.35',DECIMAL(9,2));

The result can also be successfully converted, and the running result is as shown in the figure.

How to convert mysql string to number

If you want to perform the opposite operation, that is, convert the number into a string, you can use CHAR and look at the sql statement:

SELECT CONVERT(23,CHAR);

Running results As shown below.

How to convert mysql string to number

To convert numbers into strings, you can also directly use the "''" method. The sql statement is as follows:

SELECT 123 '';, the The running results of sql are as shown in the figure.

How to convert mysql string to number

[Related recommendations: mysql video tutorial]

The above is the detailed content of How to convert mysql string to number. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How does MySQL differ from SQLite?How does MySQL differ from SQLite?Apr 24, 2025 am 12:12 AM

The main difference between MySQL and SQLite is the design concept and usage scenarios: 1. MySQL is suitable for large applications and enterprise-level solutions, supporting high performance and high concurrency; 2. SQLite is suitable for mobile applications and desktop software, lightweight and easy to embed.

What are indexes in MySQL, and how do they improve performance?What are indexes in MySQL, and how do they improve performance?Apr 24, 2025 am 12:09 AM

Indexes in MySQL are an ordered structure of one or more columns in a database table, used to speed up data retrieval. 1) Indexes improve query speed by reducing the amount of scanned data. 2) B-Tree index uses a balanced tree structure, which is suitable for range query and sorting. 3) Use CREATEINDEX statements to create indexes, such as CREATEINDEXidx_customer_idONorders(customer_id). 4) Composite indexes can optimize multi-column queries, such as CREATEINDEXidx_customer_orderONorders(customer_id,order_date). 5) Use EXPLAIN to analyze query plans and avoid

Explain how to use transactions in MySQL to ensure data consistency.Explain how to use transactions in MySQL to ensure data consistency.Apr 24, 2025 am 12:09 AM

Using transactions in MySQL ensures data consistency. 1) Start the transaction through STARTTRANSACTION, and then execute SQL operations and submit it with COMMIT or ROLLBACK. 2) Use SAVEPOINT to set a save point to allow partial rollback. 3) Performance optimization suggestions include shortening transaction time, avoiding large-scale queries and using isolation levels reasonably.

In what scenarios might you choose PostgreSQL over MySQL?In what scenarios might you choose PostgreSQL over MySQL?Apr 24, 2025 am 12:07 AM

Scenarios where PostgreSQL is chosen instead of MySQL include: 1) complex queries and advanced SQL functions, 2) strict data integrity and ACID compliance, 3) advanced spatial functions are required, and 4) high performance is required when processing large data sets. PostgreSQL performs well in these aspects and is suitable for projects that require complex data processing and high data integrity.

How can you secure a MySQL database?How can you secure a MySQL database?Apr 24, 2025 am 12:04 AM

The security of MySQL database can be achieved through the following measures: 1. User permission management: Strictly control access rights through CREATEUSER and GRANT commands. 2. Encrypted transmission: Configure SSL/TLS to ensure data transmission security. 3. Database backup and recovery: Use mysqldump or mysqlpump to regularly backup data. 4. Advanced security policy: Use a firewall to restrict access and enable audit logging operations. 5. Performance optimization and best practices: Take into account both safety and performance through indexing and query optimization and regular maintenance.

What are some tools you can use to monitor MySQL performance?What are some tools you can use to monitor MySQL performance?Apr 23, 2025 am 12:21 AM

How to effectively monitor MySQL performance? Use tools such as mysqladmin, SHOWGLOBALSTATUS, PerconaMonitoring and Management (PMM), and MySQL EnterpriseMonitor. 1. Use mysqladmin to view the number of connections. 2. Use SHOWGLOBALSTATUS to view the query number. 3.PMM provides detailed performance data and graphical interface. 4.MySQLEnterpriseMonitor provides rich monitoring functions and alarm mechanisms.

How does MySQL differ from SQL Server?How does MySQL differ from SQL Server?Apr 23, 2025 am 12:20 AM

The difference between MySQL and SQLServer is: 1) MySQL is open source and suitable for web and embedded systems, 2) SQLServer is a commercial product of Microsoft and is suitable for enterprise-level applications. There are significant differences between the two in storage engine, performance optimization and application scenarios. When choosing, you need to consider project size and future scalability.

In what scenarios might you choose SQL Server over MySQL?In what scenarios might you choose SQL Server over MySQL?Apr 23, 2025 am 12:20 AM

In enterprise-level application scenarios that require high availability, advanced security and good integration, SQLServer should be chosen instead of MySQL. 1) SQLServer provides enterprise-level features such as high availability and advanced security. 2) It is closely integrated with Microsoft ecosystems such as VisualStudio and PowerBI. 3) SQLServer performs excellent in performance optimization and supports memory-optimized tables and column storage indexes.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

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

Hot Tools

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

SecLists

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.

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)