Compound Expressions

A compound expression specifies a combination of other expressions.

compound_expression::=

Description of the illustration compound_expression.eps

You can use any built-in function as an expression (Function Expressions). However, in a compound expression, some combinations of functions are inappropriate and are rejected. For example, the LENGTH function is inappropriate within an aggregate function.

The PRIOR operator is used in CONNECT BY clauses of hierarchical queries.

The COLLATE operator determines the collation for an expression. This operator overrides the collation that the database would have derived for the expression using standard collation derivation rules.

See Also:

• Operator Precedence

• Hierarchical Queries

• COLLATE Operator

Some valid compound expressions are:

('CLARK' || 'SMITH') 
LENGTH('MOOSE') * 57 
SQRT(144) + 72 
my_fun(TO_CHAR(sysdate,'DD-MMM-YY'))
name COLLATE BINARY_CI