search
HomeDatabaseSQLWhat does the percent sign mean in sql

The percent sign (%) in SQL is a wildcard character representing any number of characters, mainly used for string comparison and fuzzy queries: String comparison: used to match character sequences that begin with a specific string. Fuzzy query: Used to match fields in a table that contain a specific sequence of characters, regardless of the remainder of the field. Regular expressions: Can be used with regular expressions in some databases to match strings with specific patterns.

What does the percent sign mean in sql

The percent sign (%) in SQL

The percent sign (%) character in SQL is Wildcard character, representing any number of characters. It is mainly used for string comparison and fuzzy query.

Usage:

  • String comparison:

    • For example, LIKE 'test%' will match all strings starting with "test", such as "test123", "test_abc".
  • Fuzzy query:

    • For example, SELECT * FROM table WHERE name LIKE '%john%' Will match all name fields containing "john" in the table, such as "John Doe", "John Smith".
  • Regular Expressions:

    • In SQL Server, the percent sign can also be used in regular expressions. (Other database systems may use different syntax)
    • For example, REGEXP_LIKE('12345%', '45$') will match a string ending with "45".

Note:

  • The percent sign does not match specific characters such as spaces.
  • If you want to match actual percent signs, you need to use escape characters (for example, LIKE '100\%').

The above is the detailed content of What does the percent sign mean in sql. 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
What are the different types of data partitioning in SQL (horizontal, vertical)?What are the different types of data partitioning in SQL (horizontal, vertical)?Mar 13, 2025 pm 02:01 PM

The article discusses horizontal and vertical data partitioning in SQL, focusing on their impact on performance and scalability. It compares benefits and considerations for choosing between them.

How to handle foreign key constraints in SQL delete rowsHow to handle foreign key constraints in SQL delete rowsMar 04, 2025 pm 05:52 PM

This article addresses deleting rows with foreign key constraints in relational databases. It details methods for handling constraint violations, including cascading deletes, restricting deletes, and setting nulls. The article emphasizes best pract

How do I use aggregate functions in SQL to summarize data (SUM, AVG, COUNT, MIN, MAX)?How do I use aggregate functions in SQL to summarize data (SUM, AVG, COUNT, MIN, MAX)?Mar 13, 2025 pm 01:50 PM

The article explains how to use SQL aggregate functions (SUM, AVG, COUNT, MIN, MAX) to summarize data, detailing their uses and differences, and how to combine them in queries.Character count: 159

What are the security risks of using dynamic SQL and how can I mitigate them?What are the security risks of using dynamic SQL and how can I mitigate them?Mar 13, 2025 pm 01:59 PM

The article discusses security risks of dynamic SQL, focusing on SQL injection, and provides mitigation strategies like using parameterized queries and input validation.

What are the different transaction isolation levels in SQL (READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, SERIALIZABLE)?What are the different transaction isolation levels in SQL (READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, SERIALIZABLE)?Mar 13, 2025 pm 01:56 PM

The article discusses SQL transaction isolation levels: READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, and SERIALIZABLE. It examines their impact on data consistency and performance, noting that higher isolation ensures greater consistency but ma

What are the ACID properties of transactions in SQL?What are the ACID properties of transactions in SQL?Mar 13, 2025 pm 01:54 PM

The article discusses the ACID properties (Atomicity, Consistency, Isolation, Durability) in SQL transactions, crucial for maintaining data integrity and reliability.

How to test SQL delete rowsHow to test SQL delete rowsMar 04, 2025 pm 05:53 PM

This article details effective testing strategies for SQL DELETE operations. It emphasizes verifying correct row deletion via pre- and post-deletion data comparisons, row counts, and negative testing. Best practices, including backups, transaction

What is the difference between SQL delete rows and truncateWhat is the difference between SQL delete rows and truncateMar 04, 2025 pm 05:49 PM

This article compares SQL's DELETE and TRUNCATE commands. DELETE removes rows individually, allowing conditional removal and transaction rollback. TRUNCATE is faster, removing all rows at once, but lacks rollback capability. Performance and data re

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

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

EditPlus Chinese cracked version

EditPlus Chinese cracked version

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

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

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.

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)