Which index should be used on the order_sum field for a query with the condition 'greater than a value'?

For a query with the condition "order_sum > value", it is optimal to use a B-Tree index (the default index in most DBMS). Such an index allows efficient execution of range queries, including conditions "greater", "less", and between values.

Example of creating an index in PostgreSQL:

CREATE INDEX idx_order_sum ON orders(order_sum);

If the order_sum field is frequently used in such queries, this index will significantly speed up the selection.