If you do not use the judgment operation to ensure that if any number is greater than 30, it is 30; otherwise, it is the original value (maximum limit on Field Values in SQL sorting), and 30 SQL statements

If you do not use the judgment operation to ensure that if any number is greater than 30, it is 30; otherwise, it is the original value (maximum limit on Field Values in SQL sorting), and 30 SQL statements

Scenario: in a database, you need to sort a specific result. When sorting, the results are sorted by different weights of several fields, but the maximum weight of one field is limited to 30.

Analysis: in SQL, is a> 30? 30: only basic operations (+-*/) and logical operations (& | xor) such as a are supported.

Answer:

(A-a % 30) & 1) * 30: When a is less than 30, a-a % 30 is 0, (0 & 1) * if the result of 30 is 0 and a is greater than or equal to 30, the final result is 30.

(A-a % 30) xor 1: When a is greater than or equal to 30, the value is 0. If a is less than 30, the result is 1.

(A-a % 30) xor 1) * (a % 30): When a is greater than or equal to 30, the value is 0. If a is less than 30, the result is.

Final: (a-a % 30) & 1) * 30 + (a-a % 30) xor 1) * (a % 30)

When a is less than 30, the partial operation before the plus sign is 0, the subsequent operation is a, and the sum is.

When a is greater than or equal to 30, the partial operation before the plus sign is 30, the subsequent operation is 0, and the sum is 30.