Oracle DECODE() Function

Syntax

DECODE(value, replacement)

Basic Example

SELECT DECODE(phone, 'No phone') AS phone_display
FROM customers;

When to use it

Use DECODE when you need a null operation in Oracle. This page is designed as a quick reference for developers, analysts, and students comparing SQL dialects.

Common mistake

A common mistake is copying syntax from another SQL dialect. Always verify function name, argument order, and formatting tokens for Oracle.

Related SQL Functions

• MySQL IFNULL() Function
• MySQL COALESCE() Function
• MySQL NULLIF() Function
• PostgreSQL COALESCE() Function
• PostgreSQL NULLIF() Function
• SQL Server ISNULL() Function

FAQ

Is DECODE available in every SQL database?

Not always. Function names and argument behavior can differ across SQL engines.

Can I use this in SELECT queries?

Yes. Most SQL functions are commonly used in SELECT and often in WHERE, ORDER BY, and GROUP BY depending on the function.