Vertica Analytics Platform Version 9.2.x Documentation

SQL Functions

Functions return information from the database.Except for Vertica-specific functions, you can use a function anywhere an expression is allowed.

This chapter describes each function that Vertica supports. The Behavior Type section of these descriptions categorizes the function's return behavior as one of the following:


Immutable (invariant)

When run with a given set of arguments, immutable functions such as AVG() always produce the same result, regardless of environment or session settings such as locale.


Stable

When run with a given set of arguments, stable functions produce the same result within a single query or scan operation. However, a stable function can produce different results when issued under different environments or at different times, such as change of locale and time zone—for example, SYSDATE() and 'today'.


Volatile

Regardless of their arguments or environment, volatile functions can return a different result with each invocation—for example, UUID_GENERATE().

All Vertica-specific functions are volatile; thus, the descriptions of these functions omit a Behavior Type section.