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Databases SQL Reporting by Example Orientation: Selecting Data Orientation Quiz

Posted by i as
i as
544 Points

Can anybody tell me why the answer is 6?

I just don't understand it's going to be 6

1 Answer

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

I assume you're asking about this question:

The EMPLOYEES table has 23 columns and the JOBS table has 4. How many COLUMNS does the following query return?

SELECT FIRST_NAME, LAST_NAME, JOBS.*
FROM EMPLOYEES
JOIN JOBS ON EMPLOYEES.JOB_ID = JOBS.ID;

If you look at what is being SELECTed, you'll see that it is FIRST_NAME, LAST_NAME, and JOBS.* which means "everything from JOBS". So that's 2 name columns, and all 4 columns from JOBS, for a total of 6. Make sense now?

i as
i as
544 Points

I misunderstood the concepts before，thank you for your explanation.