Explanatory Question
When to use single-column index or a composite index?
Read the answer carefully and go through the related questions on the right side to improve your understanding of this topic.
To create a single-column index or a composite index, take into consideration the column(s) that you may use very frequently in a query's WHERE clause as filter conditions.
Should there be only one column used, a single-column index should be the choice. Should there be two or more columns that are frequently used in the WHERE clause as filters, the composite index would be the best choice.
First read the answer fully, then try to explain it in your own words. After that, open a few related questions and compare the concepts. This method helps you remember the topic for a longer time and improves exam preparation.