Is it okay if we don't use GROUP BY?

Using GROUP BY is only necessary when you want to aggregate data across rows, such as calculating SUM, AVG, COUNT, MAX, or MIN for each group. If your query does not include any aggregate functions or you are selecting all columns without grouping, you can omit GROUP BY. However, if you mix aggregated columns with non‑aggregated columns without grouping, the query will be invalid in most SQL dialects. Therefore, you should include GROUP BY only when you need to produce grouped results; otherwise, it is fine to leave it out.