Advanced
SQL
Q85 / 100
What is the difference between "covering index" and a regular index?
Correct! Well done.
Incorrect.
The correct answer is B) A covering index includes all the columns needed to satisfy a query (in the index itself), allowing the database to answer the query without accessing the underlying table data ("index-only scan")
B
Correct Answer
A covering index includes all the columns needed to satisfy a query (in the index itself), allowing the database to answer the query without accessing the underlying table data ("index-only scan")
Explanation
When an index contains every column referenced by a query (via key columns and/or included columns), the database can satisfy the query entirely from the index, avoiding extra lookups to the table ("covering" the query).
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85/100