How Can I Use Special Characters Effectively in SQL's LIKE Clause for Pattern Matching?

SQL LIKE Clause: A Comprehensive List of Special Characters

The SQL LIKE clause enables users to perform pattern matching queries. To facilitate this, special characters allow for flexible matching criteria. Here's a comprehensive list:

Core Special Characters (Common across DBMS)

• %: Matches any string of any length (zero or more characters)
• _: Matches any single character

Additional Special Characters in SQL Server:

• [specifier]: Matches any character within a specified range (e.g., [a-z] matches any lowercase letter)
• ¹: Matches any character outside a specified range
• ESCAPE clause: Escapes the following character (e.g., 0!%%' ESCAPE '!' evaluates 30% as true)

Additional Special Characters in PostgreSQL (SIMILAR TO Operator):

PostgreSQL Wildcard Characters:

• %: Matches any string of any length
• _: Matches any single character

PostgreSQL Matching Operators:

• [specifier]: Matches any character within a specified range
• ¹: Matches any character outside a specified range
• |: Matches either of two alternatives
• *: Repetition of the previous item zero or more times
• : Repetition of the previous item one or more times
• (): Groups items together

Other DBMS Considerations:

While SQL Server and PostgreSQL offer the most comprehensive set of special characters, most other DBMS support the core special characters (% and _). Check the respective documentation for DBMS-specific details.

Conclusion:

This list serves as a comprehensive reference for the special characters used in SQL LIKE clauses. By leveraging these characters, developers can create powerful patterns to filter and retrieve data from their databases.

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1. specifier ↩

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