mysql只有主键可以自增

-- 创建辅助表
CREATE TABLE auto_increment_counter (
    table_name VARCHAR(50) NOT NULL,
    column_name VARCHAR(50) NOT NULL,
    next_value INT NOT NULL,
    PRIMARY KEY (table_name, column_name)
);

-- 初始化辅助表
INSERT INTO auto_increment_counter (table_name, column_name, next_value)
VALUES ('your_table', 'your_column', 1);

-- 创建触发器
DELIMITER $$
CREATE TRIGGER before_your_table_insert
BEFORE INSERT ON your_table
FOR EACH ROW
BEGIN
    DECLARE next_val INT;
    UPDATE auto_increment_counter
    SET next_value = LAST_INSERT_ID(next_value + 1)
    WHERE table_name = 'your_table' AND column_name = 'your_column';
    SET NEW.your_column = LAST_INSERT_ID();
END$$
DELIMITER ;

-- 插入记录
INSERT INTO your_table (other_columns, your_column) VALUES ('value1', NULL);