Example of using gbase 8A OLAP function group by grouping sets

GBase 8a Of group grouping sets function , For those in brackets n Each field or expression is done GROUP BY operation , Finally, combine the results . Equivalent to multiple separate group by Then make another one union all operation .

grammar

GROUP BY GROUPING SETS( (…),(…),…)

explain
GROUP BY GROUPING SETS (A,B,C) (A、B、C Stands for... In grammar “(…)”)
First of all, (A) Conduct GROUP BY, Then on (B) Conduct GROUP BY, And then we do GROUP BY, Finally, combine all the results together ( amount to UNION ALL operation ), If n One or more of the fields or expressions do not appear in a group GROUP BY Back , use NULL Replace fields or expressions that do not appear .

Examples
Sample data
Simple student subject examination records .

gbase> select * from score;
+--------+---------+-------+
| name   | subject | score |
+--------+---------+-------+
|  Wang hai    |  Chinese language and literature     |    86 |
|  Wang hai    |  mathematics     |    83 |
|  Wang hai    |  English     |    93 |
|  Tao Jun    |  Chinese language and literature     |    88 |
|  Tao Jun    |  mathematics     |    84 |
|  Tao Jun    |  English     |    94 |
|  Liu Ke    |  Chinese language and literature     |    80 |
|  Liu Ke    |  mathematics     |    86 |
|  Liu Ke    |  English     |    88 |
|  Li Chun    |  Chinese language and literature     |    89 |
|  Li Chun    |  mathematics     |    80 |
|  Li Chun    |  English     |    87 |
+--------+---------+-------+
12 rows in set (Elapsed: 00:00:00.01)

Get the summary results of students and subjects

gbase> select name,subject,sum(score) from score group by grouping sets(name,subject);
+--------+---------+------------+
| name   | subject | sum(score) |
+--------+---------+------------+
| NULL   |  Chinese language and literature     |        343 |
| NULL   |  mathematics     |        333 |
| NULL   |  English     |        362 |
|  Wang hai    | NULL    |        262 |
|  Tao Jun    | NULL    |        266 |
|  Liu Ke    | NULL    |        254 |
|  Li Chun    | NULL    |        256 |
+--------+---------+------------+
7 rows in set (Elapsed: 00:00:00.02)

Multiple Sets In between, too union all Relationship . This example simply converts the previous use case's 2 Conditions , Split up . The result is the same .

gbase> select name,subject,sum(score) from score group by grouping sets((name),(subject));
+--------+---------+------------+
| name   | subject | sum(score) |
+--------+---------+------------+
| NULL   |  Chinese language and literature     |        343 |
| NULL   |  mathematics     |        333 |
| NULL   |  English     |        362 |
|  Wang hai    | NULL    |        262 |
|  Tao Jun    | NULL    |        266 |
|  Liu Ke    | NULL    |        254 |
|  Li Chun    | NULL    |        256 |
+--------+---------+------------+
7 rows in set (Elapsed: 00:00:00.02)

gbase> select name,subject,sum(score) from score group by grouping sets(name,(name,subject));
+--------+---------+------------+
| name   | subject | sum(score) |
+--------+---------+------------+
|  Wang hai    |  Chinese language and literature     |         86 |
|  Wang hai    |  mathematics     |         83 |
|  Wang hai    |  English     |         93 |
|  Tao Jun    |  Chinese language and literature     |         88 |
|  Tao Jun    |  mathematics     |         84 |
|  Tao Jun    |  English     |         94 |
|  Liu Ke    |  Chinese language and literature     |         80 |
|  Liu Ke    |  mathematics     |         86 |
|  Liu Ke    |  English     |         88 |
|  Li Chun    |  Chinese language and literature     |         89 |
|  Li Chun    |  mathematics     |         80 |
|  Li Chun    |  English     |         87 |
|  Wang hai    | NULL    |        262 |
|  Tao Jun    | NULL    |        266 |
|  Liu Ke    | NULL    |        254 |
|  Li Chun    | NULL    |        256 |
+--------+---------+------------+
16 rows in set (Elapsed: 00:00:00.04)

In the second example above , The first part is name, The second part is (name,subject) Two fields together .

Be careful , Don't think about repetition , That is, you can write more name.

gbase> select name,subject,sum(score) from score group by grouping sets(name,name,subject);
+--------+---------+------------+
| name   | subject | sum(score) |
+--------+---------+------------+
| NULL   |  Chinese language and literature     |        343 |
| NULL   |  mathematics     |        333 |
| NULL   |  English     |        362 |
|  Wang hai    | NULL    |        262 |
|  Tao Jun    | NULL    |        266 |
|  Liu Ke    | NULL    |        254 |
|  Li Chun    | NULL    |        256 |
|  Wang hai    | NULL    |        262 |
|  Tao Jun    | NULL    |        266 |
|  Liu Ke    | NULL    |        254 |
|  Li Chun    | NULL    |        256 |
+--------+---------+------------+
11 rows in set (Elapsed: 00:00:00.03)