Functions are similar to operators in that they manipulate data items and return a result. Functions differ from operators in the format of their arguments. This format enables them to operate on zero, one, two, or more arguments:

function(argument, argument, ...) 

A function without any arguments is similar to a pseudocolumn (refer to Pseudocolumns). However, a pseudocolumn typically returns a different value for each row in the result set, whereas a function without any arguments typically returns the same value for each row.

This chapter contains these sections:

• About SQL Functions

• Single-Row Functions

  • Numeric Functions

  • Character Functions Returning Character Values

  • Character Functions Returning Number Values

  • Character Set Functions

  • Collation Functions

  • Datetime Functions

  • General Comparison Functions

  • Conversion Functions

  • Large Object Functions

  • Collection Functions

  • Hierarchical Functions

  • Oracle Machine Learning for SQL Functions

  • XML Functions

  • JSON Functions

  • Encoding and Decoding Functions

  • NULL-Related Functions

  • Environment and Identifier Functions

• Aggregate Functions

• Analytic Functions

• Object Reference Functions

• Model Functions

• OLAP Functions

• Data Cartridge Functions

• About User-Defined Functions