A system, method, and computer-readable medium for optimizing complex SQL statements using a region divided preferential SQL rewrite operation. The region divided preferential SQL rewrite operation makes it possible for a user to inference a machine SQL statement rewrite operation to optimize the SQL statement with more or less focus on different regions of the SQL. This operation combines the strength of using heuristic knowledge and understanding of data to rewrite the region of the SQL statement where the problem originates with the precision and efficiency of a machine SQL statement rewrite operation. More specifically, optimizing a complex SQL statement includes a region division operation during which a SQL statement is divided into multiple regions, a user preference assignment process in which the user defines different attention level for different regions, and a region preferential rewrite operation in which the SQL statement is rewritten with consideration to the attention level defined for each region of the SQL statement.