Currently INTERVAL literals can appear in context of the DATE_ADD function and the operator +.
We will change INTERVAL from a DATE_ADD and + specific syntax to a full-functional data type, so intervals can appear in all context where a regular data type can, including:
- INTERVAL table fields
- INTERVAL stored routine variables, parameters, function return values
- Hybrid built-in functions and operators, such as COALESCE, IF, CASE, LEAST, GREATEST.
- MIN and MAX aggregate functions