So far we learnt about Different types of Joins in SAP HANA
and Text Join
In this article we will learn about a temporal joins in HANA.
A temporal join indicates the time interval mapping between the master data and the transaction data for which you want to fetch the records.
You create a temporal join using the temporal column that specifies the time interval with the start and the end date. The result set is fetched based on the time interval mapped using the temporal column.
A record is only included in the results set if the time interval lies within the valid time interval. A time interval is assigned to each record in the results set. The records are valid for the duration of the interval to which they are assigned.
You use temporal conditions to indicate whether to include or exclude the value of the FROM and TO date fields while executing the join condition.
In the logical join, you can create a temporal join between the date field of the fact table to an interval (to and from) field of the attribute view. The temporal join must start from the fact table such that the single column must be in the fact table and, the to and from columns must be in the table that is directly joined to the fact table. The join type must be Referential. The supported data types are: timestamp, date, and integer.