정답: B  🗳️

설명: (Fast2test 회원만 볼 수 있음)

정답:

Explanation:
* ON # m.maintenanceId = i.maintenanceId
* WHERE # m.LastModifiedUtc < > i.LastModifiedUtc
The correct drag-and-drop completion is:
* ON m.maintenanceId = i.maintenanceId
* WHERE m.LastModifiedUtc < > i.LastModifiedUtc
This satisfies the requirement to ensure that when a row in MaintenanceEvents changes, the corresponding LastModifiedUtc value is updated to the current system time, while also helping avoid unnecessary repeat updates.
The inserted pseudo-table in a SQL Server AFTER UPDATE trigger contains the rows that were just updated.
To update the matching row in the base table correctly, the trigger must join the target table row to the corresponding row in inserted by the table's primary key. In this schema, MaintenanceId is the primary key for MaintenanceEvents, so the correct join is m.maintenanceId = i.maintenanceId . Joining on VehicleId would be incorrect because multiple maintenance rows could exist for the same vehicle, which could update unintended rows. Microsoft's trigger documentation explains that inserted and deleted are used to work with the affected rows and that multi-row logic should be based on proper key matching.
The WHERE m.LastModifiedUtc < > i.LastModifiedUtc predicate is used to prevent the trigger from re- updating rows where the timestamp already matches the value in inserted. That reduces redundant writes and supports the requirement to avoid recursive or repeated update behavior. In practice, this means the trigger updates only rows whose current stored timestamp differs from the just-updated version. This is the exam- appropriate pattern for a self-updating timestamp column in an AFTER UPDATE trigger.

정답:

Explanation:
* Sales # A clustered columnstore index
* Products # A clustered rowstore index
For Sales , the correct choice is a clustered columnstore index . Microsoft identifies clustered columnstore indexes as the standard storage choice for large fact tables and analytical/data-warehouse workloads . The Sales table is 10 TB, loaded in nightly batches, and its reporting queries scan large portions of the table and perform aggregations such as SUM(TotalSale) . Those are exactly the workload characteristics that benefit from columnstore storage, batch-mode execution, aggregate pushdown, and high compression. Microsoft also notes that clustered columnstore indexes can provide substantial storage reduction compared with traditional uncompressed rowstore structures, which directly supports the requirement to minimize storage requirements .
For Products , the correct choice is a clustered rowstore index . Microsoft states that rowstore B-tree indexes perform best for point lookups, equality searches, and small-range retrieval , whereas columnstore is optimized for large analytical scans. Since Products is relatively small and primarily supports point lookups and joins to Sales , a rowstore structure is the better fit.
A nonclustered columnstore index would retain the underlying rowstore and add another compressed copy of selected columns, increasing storage. That is more appropriate for real-time analytics over an OLTP table, not for this dedicated large analytical fact table.

정답:

Explanation:
where exists 2. where p.PatientID = pr.PatientID Otherwise we filter PatientID twice. Having in the subquery does not work without group by and the date filter does not work without where.