+----------------------------------------------------------+
|                   QUERY 1 (0.5734 sec)                   |
+----------------------------------------------------------+
select day, ad, sum(clicks), sum(impressions) from tracki...

__ Overall stats ___________________________________________
   Elapsed time                              0.573
   Optimizer cost                        21257.999

__ Table and index accesses ________________________________
   Table locks acquired                      1
   Table scans                               0
     Join                                    0
   Index range scans                         0
     Join without check                      0
     Join with check                         0
   Rows sorted                              31
     Range sorts                             0
     Merge passes                            0
     Table scans                             1

+----------------------------------------------------------+
|                   QUERY 2 (0.5127 sec)                   |
+----------------------------------------------------------+
select day, ad, sum(clicks), sum(impressions) from tracki...

__ Overall stats ___________________________________________
   Elapsed time                              0.513
   Optimizer cost                        10537.399

__ Table and index accesses ________________________________
   Table locks acquired                      1
   Table scans                               0
     Join                                    0
   Index range scans                         0
     Join without check                      0
     Join with check                         0
   Rows sorted                              31
     Range sorts                             0
     Merge passes                            0
     Table scans                             1

+----------------------------------------------------------+
|                   QUERY 3 (0.0245 sec)                   |
+----------------------------------------------------------+
select day, ad, sum(clicks), sum(impressions) from tracki...

__ Overall stats ___________________________________________
   Elapsed time                              0.024
   Optimizer cost                        86467.633

__ Table and index accesses ________________________________
   Table locks acquired                      1
   Table scans                               0
     Join                                    0
   Index range scans                         1
     Join without check                      0
     Join with check                         0
   Rows sorted                               0
     Range sorts                             0
     Merge passes                            0
     Table scans                             0

+----------------------------------------------------------+
|                         SUMMARY                          |
+----------------------------------------------------------+

__ Overall stats ___________________________________________
   Total elapsed time                        1.111
   Questions                                 3
     COMMIT                                  0
     DELETE                                  0
     DELETE MULTI                            0
     INSERT                                  0
     INSERT SELECT                           0
     REPLACE                                 0
     REPLACE SELECT                          0
     SELECT                                  3
     UPDATE                                  0
     UPDATE MULTI                            0
   Optimizer cost                       118263.031

__ Table and index accesses ________________________________
   Table locks acquired                      3
   Table scans                               0
     Join                                    0
   Index range scans                         1
     Join without check                      0
     Join with check                         0
   Rows sorted                              62
     Range sorts                             0
     Merge passes                            0
     Table scans                             2