Using Pseudocolumns, Sequences, and SQL Functions

With SQL built-in functions, you can manipulate character, numeric, and date data in SQL statements to change how the data is displayed or to convert the data for insertion in a column of a table. You can also perform operations on a collection of data with aggregate functions.

Pseudocolumns are built-in values that provide specific information with a query and are similar to functions without arguments. However, functions without arguments typically return the same value for every row in the result set, whereas pseudocolumns typically return a different value for each row.

This section contains the following topics:

Using ROWNUM, SYSDATE, and USER Pseudocolumns With SQL
Using Arithmetic Operators
Using Numeric Functions
Using Character Functions
Using Date Functions
Using Conversion Functions
Using Aggregate Functions
Using NULL Value Functions
Using Conditional Functions