Aggregation example
The example used in aggregation schema documentation is based on a project management system, that stores time sheets per project and person. The grouping level is projectId(STRING), personId(STRING), iDate(IDate). IDate is a complex grouping dimension that has got three attributes (year, month and day). Complex dimension attributes provide aggregation levels for each subordinated dimension attribute, i.e. aggregation levels provided are year, year, month and year, month,day.
The aggregated variable is the time spent on a certain project or by a certain person or in a certain time interval.
STRUCT IDate {
INT(2) year;
INT(2) month;
INT(2) day; };
SELECT ( INT(10,2) time = sum(duration) ) HIERARCHY(SIMPLE)
FROM (TimeSheet)
GROUP BY ( STRING(10) personId = person(0).id,
STRING(10) projectId = task(0).GetProject().id,
IDate iDate = GetIDate(start) );
GetProject() provides the project a task in a hierarchical task structure belongs too. This may also be the project itself, which also is a task.
GetIDate() is a function that creates an IDate structure from a database date value.