What indexes would you add to a table and why?

The choice of indexes depends on the table structure and the queries performed on it. Typically, the following are added:

• Indexes on columns involved in WHERE — to speed up filtering.
• Indexes on columns involved in JOIN — for quick table joins.
• Unique indexes — to ensure data uniqueness and speed up searches.
• Composite indexes — if filtering by multiple columns simultaneously is common.

For example, if there is an orders table with columns order_id, customer_id, order_date, and orders are often searched by customer and date, it is advisable to add an index on (customer_id, order_date).

It is important not to create too many indexes, as they slow down insert and update operations.