Group by RollUp&Group by CUBE&GroupBy 区别

1、如果是ROLLUP(A, B, C)的话，首先会对(A、B、C)进行GROUP BY，然后对(A、B)进行GROUP BY，然后是(A)进行GROUP BY，最后对全表进行GROUP BY操作。

2、如果是GROUP BY CUBE(A, B, C)，则首先会对(A、B、C)进行GROUP BY，然后依次是(A、B)，(A、C)，(A)，(B、C)，(B)，(C)，最后对全表进行GROUP BY操作。

举例：SQL> select grouping(index_type) g_ind,grouping(status) g_st,index_type,status,count(*) from t group by rollup(index_type,status) order by 1,2;
 
     G_IND       G_ST INDEX_TYPE                  STATUS     COUNT(*)
---------- ---------- --------------------------- -------- ----------
         0          0 LOB                         N/A               1
         0          0 LOB                         VALID           587
         0          0 FUNCTION-BASED NORMAL       VALID            16
         0          0 FUNCTION-BASED DOMAIN       VALID             1
         0          0 IOT - TOP                   VALID           103
         0          0 CLUSTER                     VALID            10
         0          0 NORMAL                      VALID          3171
         0          0 NORMAL                      N/A              94
         0          0 BITMAP                      VALID             1
         0          1 FUNCTION-BASED NORMAL                        16
         0          1 NORMAL                                     3265
         0          1 IOT - TOP                                   103
         0          1 FUNCTION-BASED DOMAIN                         1
         0          1 BITMAP                                        1
         0          1 CLUSTER                                      10
         0          1 LOB                                         588
         1          1                                            3984
 
17 rows selected

 

SQL> select grouping(index_type) g_ind,grouping(status) g_st,index_type,status,count(*) from t group by cube(index_type,status) order by 1,2;
 
     G_IND       G_ST INDEX_TYPE                  STATUS     COUNT(*)
---------- ---------- --------------------------- -------- ----------
         0          0 LOB                         N/A               1
         0          0 CLUSTER                     VALID            10
         0          0 FUNCTION-BASED NORMAL       VALID            16
         0          0 NORMAL                      VALID          3171
         0          0 IOT - TOP                   VALID           103
         0          0 LOB                         VALID           587
         0          0 FUNCTION-BASED DOMAIN       VALID             1
         0          0 BITMAP                      VALID             1
         0          0 NORMAL                      N/A              94
         0          1 IOT - TOP                                   103
         0          1 CLUSTER                                      10
         0          1 NORMAL                                     3265
         0          1 BITMAP                                        1
         0          1 LOB                                         588
         0          1 FUNCTION-BASED NORMAL                        16
         0          1 FUNCTION-BASED DOMAIN                         1
         1          0                             N/A              95
         1          0                             VALID          3889
         1          1                                            3984
 
19 rows selected