You have a table, TableOne, with many columns.
After analysis you conclude that, based on WHERE and JOIN clauses:
- 40% of the queries access Col1, Col2 and Col3
- 25% of the queries access only Col1
- 25% of the queries access only Col3
- 10% of queries access variations of the above three (Col1 & Col3, Col2 & Col3, Col2, Col1 & Col2) and other columns not listed but existing in the table
You decide to create a single index on Col1, Col2, Col3.
Is this the only index you need on the table to satisfy the bulk of queries based on the above analysis or would others be beneficial? Why or why not?