Complete the lab with a grouped SQL report that combines related tables without double-counting.
Guided practice · Combine and Summarize Data
Guided Lab: Combine and Summarize Data in SQL and Relational Databases
SQL and Relational Databases — Combine and Summarize Data lab: Return each customer with order count and total order value, including customers with no orders, then filter to customers whose total exceeds a chosen threshold.
Outcome summary
Know what success looks like before you begin
Save verification evidence: query output, expected row counts, and a check for unmatched or duplicated rows.
- I completed the module-specific practice task.
- I produced a grouped SQL report that combines related tables without double-counting.
- I saved query output, expected row counts, and a check for unmatched or duplicated rows.
- I diagnosed and corrected one realistic Combine and Summarize Data failure.
Stop before using production credentials, important data, shared permissions, live infrastructure, or destructive commands that are not required by the lab.
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Lab brief
Know the problem and the evidence you need
Return each customer with order count and total order value, including customers with no orders, then filter to customers whose total exceeds a chosen threshold.
a grouped SQL report that combines related tables without double-counting
Complete the task, verify query output, expected row counts, and a check for unmatched or duplicated rows, then diagnose one failure that is specific to Combine and Summarize Data.
Combine related tables with joins, summarize rows with aggregate functions, group results correctly, and recognize when joins multiply rows unexpectedly.
Safety and setup
Prepare before changing anything
Have this ready
- Create small customers and orders tables with a primary-key/foreign-key relationship.
- Insert enough sample rows to include a customer with multiple orders and a customer with no orders.
- Write the expected row count before running the join.
Field checks
0 of 5 checks completeRun the lab
Complete one check at a time. Record the evidence before moving on.
Interpret results
Match the evidence to the next action
If you seeNext action
The expected result appears and the boundary case behaves correctly
Save the result and continue to the module checkpoint.
The normal case works but the failure or boundary case does not
Return to the diagnostic step and inspect the module-specific state or output before changing more code.
The result changes between runs
Compare the relevant input, dependency, configuration, data, state, or runtime version for this module.
Choose the next action
Complete the lab when you can reproduce the working result, explain the important module decision, and recover from the tested failure.
Confirm the evidence you produced
Finished record: a grouped SQL report that combines related tables without double-counting
- I completed the module-specific practice task.
- I produced a grouped SQL report that combines related tables without double-counting.
- I saved query output, expected row counts, and a check for unmatched or duplicated rows.
- I diagnosed and corrected one realistic Combine and Summarize Data failure.