mysql 反向索引

-- 创建一个示例表
CREATE TABLE example (
    id INT PRIMARY KEY,
    name VARCHAR(255)
);

-- 插入一些示例数据
INSERT INTO example (id, name) VALUES (1, 'Alice');
INSERT INTO example (id, name) VALUES (2, 'Bob');
INSERT INTO example (id, name) VALUES (3, 'Charlie');

-- 创建一个自定义函数来反转字符串
DELIMITER $$
CREATE FUNCTION reverse_string(str VARCHAR(255)) RETURNS VARCHAR(255)
BEGIN
    DECLARE reversed VARCHAR(255);
    SET reversed = '';
    DECLARE i INT DEFAULT LENGTH(str);
    WHILE i > 0 DO
        SET reversed = CONCAT(SUBSTRING(str, i, 1), reversed);
        SET i = i - 1;
    END WHILE;
    RETURN reversed;
END$$
DELIMITER ;

-- 使用自定义函数创建反向索引
CREATE INDEX idx_name_reverse ON example (reverse_string(name));