Grouping and regrouping using aggregation
Grouping and regrouping of data using aggregation is disclosed. In one aspect of this disclosure, data can be grouped based on some expressions, and then this result can be regrouped based on other expressions which may utilize aggregates computed in the context of the first group. Such regrouping is performed on a group basis—as opposed to being regrouped, for example, on a row basis. The grouping and regrouping can employ various logical expressions that may incorporate the aggregates. Moreover, regrouping of regrouping can be performed, and the mentioned logical expressions can be based on groups of various scopes.
1 . A system for grouping and regrouping data using aggregation, comprising:
a grouping module for grouping data into at least one group instance, wherein the grouping module groups the data using at least one grouping expression; and
a regrouping module for regrouping the at least one group instance, wherein the regrouping module regroups the at least one group instance on a group instance by group instance basis into at least one regrouped group instance, using the at least one regrouping expression.
2 . The system according to claim 1 , wherein the regrouping expression uses at least one aggregate.
3 . The system according to claim 1 , wherein the regrouping module performs regrouping based in part on an aggregate computed within a group of higher scope than the at least one group instance.
4 . The system according to claim 1 , wherein the last one regrouping module performs regrouping based in part on an aggregate computed within a group of the same scope as the at least one group.
5 . The system according to claim 1 , wherein the regrouping module performs regrouping based on a scalar value.
6 . The system according to claim 1 , wherein the system regroups the at least one regrouped group instance.
7 . The system according to claim 1 , wherein the regrouped data is further grouped to form a hierarchy of groups.
8 . A method for grouping and regrouping data in a database using aggregation, comprising:
grouping a first data into a first group in order to configure the first group into a first data set on which a first aggregate function can be performed;
grouping a second data into a second group in order to configure the second group into a second data set on which a second aggregate function can be performed;
performing the first aggregate function on the first data set;
performing the second aggregate function on the second data set; and
regrouping at least one of the first group and the second group into a third group, wherein the third group is formed based on one of the first group and the second group.
9 . The method according to claim 8 , further comprising of using a first grouping expression to group the first group.
10 . The method according to claim 8 , further comprising of using a second grouping expression to group the second group.
11 . The method according to claim 8 , wherein the regrouping is performed using a regrouping expression.
12 . The method according to claim 11 , wherein the regrouping expression uses a regrouping aggregate.
13 . The method according to claim 8 , further comprising of configuring the first aggregate function to be the same as the second aggregate function.
14 . The method according to claim 8 , wherein the regrouping regroups both the first group and the second group into the third group.
15 . The method according to claim 8 , wherein the third group is regrouped again into a fourth group.
16 . The method according to claim 15 , wherein the fourth group is formed using a regrouping expression.
17 . A computer readable medium bearing executable instructions for grouping and regrouping data in a database using aggregation, comprising:
grouping data into a first group;
aggregating the first group; and
regrouping the first group into a second group, wherein the regrouping uses a regrouping expression.
18 . The computer readable medium according to claim 17 , further comprising regrouping the second group.
19 . The computer readable medium according to claim 17 , wherein the regrouping expression is based on a group of the same scope as the first group.
20 . The computer readable medium according to claim 17 , wherein the regrouping expression is based on a group of a different scope than the first group.