Stop Adding Indexes. Do This Instead

Adding indexes blindly to fix slow SQL queries is a common but flawed approach. Using functions on indexed columns (like wrapping a date column in YEAR()) prevents the database from using those indexes efficiently, forcing full table scans. The fix is often to rewrite the query logic — for example, replacing a function-based date filter with a range filter — so existing indexes can be used without adding new ones. Indexes should support well-written queries, not compensate for poorly written ones. Understanding what a query actually does before touching indexes is the key mindset shift.