Case when syntax in SQL statements and similar methods in Oracle

Case when syntax in SQL statements and similar methods in Oracle I. Basic Concepts and examples case when is the syntax of SQL statements, rather than the language www.2cto.com of a specific database I: select num, name, (case classnowhen '1' Class 1 'when' 2 'then' Class 2 'else' other classs' end) as classnamefrom student Method 2: select num, name, (case when classno = '1' then' Class 1 'when classno = '2' then' Class 2 'else' other class' end) as classname from student www.2cto.com 2. Other methods in Oracle 1. The decode function plays a similar role in Oracle select num, name, decode (classno, '1', 'class1 ', '2', 'second class', 'other class') as classname from student 2. if else in PL/SQL can also achieve this effect.