Is an index created from multiple columns organized in a specific order?

An index created from multiple columns (composite index) always has a specific order of columns, which is important for its operation. The order of columns in the index affects which queries it can efficiently serve.

For example, if an index is created on columns (A, B), it is effectively used for queries filtering by A or by both A and B together, but not for queries filtering only by B.

Thus, an index is not "organized without a specific order" — the order of columns is strictly fixed and influences query performance.