COMMENT ON AGGREGATE FUNCTION
Adds, revises, or removes a comment on an aggregate function.
	Adds, revises, or removes a comment on an aggregate function. Each object can have one comment. Comments are stored in the system table 
COMMENTS.
Syntax
COMMENT ON AGGREGATE FUNCTION [[database.]schema.]function (function-args) IS { 'comment' | NULL };
Parameters
- [- database- .]- schema
- Database and schema. The default schema is - public. If you specify a database, it must be the current database.
- function
- The name of the aggregate function with which to associate the comment.
- function-args
- The function arguments.
- comment
- Specifies the comment text to add. If a comment already exists for this function, this overwrites the previous one.
Comments can be up to 8192 characters in length. If a comment exceeds that limitation, Vertica truncates the comment and emits a message. 
- NULL
- Removes an existing comment.
Privileges
Non-superuser: object owner
Examples
The following example adds a comment to the APPROXIMATE_MEDIAN(x FLOAT) function:
=> COMMENT ON AGGREGATE FUNCTION APPROXIMATE_MEDIAN(x FLOAT) IS 'alias of APPROXIMATE_PERCENTILE with 0.5 as its parameter';
The following example removes a comment from the APPROXIMATE_MEDIAN(x FLOAT) function:
=> COMMENT ON AGGREGATE FUNCTION APPROXIMATE_MEDIAN(x FLOAT) IS NULL;