expression:
 case-expression
| constant
| [correlation-name.]column-name
| - expression
| expression operator expression
| ( expression )
| function-name ( expression, ... )
| if-expression
| special value
| ( subquery )
| variable-name
| sequence-expression

case-expression :
CASE expression
WHEN expression
THEN expression,...
[ ELSE expression ]
END

alternative form of case-expression :
CASE
WHEN search-condition
THEN expression, ...
[ ELSE expression ]
END

constant :
 integer  | number  | string | host-variable

special-value :
 CURRENT { DATE  |  TIME  |  TIMESTAMP  }
| NULL
| SQLCODE
| SQLSTATE
| USER

if-expression :
IF condition
THEN expression
[ ELSE expression ]
ENDIF

sequence-expression :
sequence-name.[ CURRVAL | NEXTVAL ]
FROM table-name

operator:
{  +  |  -  |  *  |  /  |  ||  |  % }

Expressions are used in many different places.

Expressions are formed from several different kinds of elements. These are discussed in the sections on functions and variables.

You must be connected to the database in order evaluate expressions.

None.

• Constants in expressions
• Special values
• Column names in expressions
• SQL functions
• Subqueries in expressions
• Search conditions
• SQL data types
• Variables
• CASE expressions