|Oracle® Database SQL Reference
10g Release 1 (10.1)
Part Number B10759-01
An expression is a combination of one or more values, operators, and SQL functions that evaluates to a value. An expression generally assumes the datatype of its components.
This simple expression evaluates to 4 and has datatype
NUMBER (the same datatype as its components):
The following expression is an example of a more complex expression that uses both functions and operators. The expression adds seven days to the current date, removes the time component from the sum, and converts the result to
You can use expressions in:
The select list of the
A condition of the
WHERE clause and
VALUES clause of the
SET clause of the
For example, you could use an expression in place of the quoted string
'Smith' in this
SET last_name = 'Smith';
SET clause has the expression
last_name) instead of the quoted string '
SET last_name = INITCAP(last_name);
Expressions have several forms, as shown in the following syntax:
Oracle Database does not accept all forms of expressions in all parts of all SQL statements. Please refer to the individual SQL statements in Chapter 10 through Chapter 19 for information on restrictions on the expressions in that statement.
You must use appropriate expression notation whenever
expr appears in conditions, SQL functions, or SQL statements in other parts of this reference. The sections that follow describe and provide examples of the various forms of expressions.