Simple Expressions

A simple expression specifies a column, pseudocolumn, constant, sequence number, or null.

simple_expression::=
Description of simple_expression.gif follows

Description of the illustration simple_expression.gif

In addition to the schema of a user, schema can also be "PUBLIC" (double quotation marks required), in which case it must qualify a public synonym for a table, view, or materialized view. Qualifying a public synonym with "PUBLIC" is supported only in data manipulation language (DML) statements, not data definition language (DDL) statements.

You can specify ROWID only with a table, not with a view or materialized view. NCHAR and NVARCHAR2 are not valid pseudocolumn datatypes.

See Also:

Chapter 3, " Pseudocolumns" for more information on pseudocolumns and subquery_factoring_clause for information on query_name

Some valid simple expressions are:

employees.last_name 
'this is a text string'
10 
N'this is an NCHAR string'