Explain the order of executing an SQL query at the operator level.

The order of executing an SQL query at the operator level is usually as follows:

1. FROM — selecting tables and performing joins.
2. WHERE — filtering rows based on a condition.
3. GROUP BY — grouping rows by specified columns.
4. HAVING — filtering grouped data.
5. SELECT — selecting necessary columns and calculating expressions.
6. DISTINCT — removing duplicates from the result.
7. ORDER BY — sorting the result.
8. LIMIT / OFFSET — limiting the number of returned rows.

This order is important for understanding how the query is processed and optimized by the DBMS.