-- 历史版本记下源文件地址。可重复执行。
SET NAMES utf8mb4;

SET @ddl = (
  SELECT IF(
    EXISTS (
      SELECT 1 FROM information_schema.COLUMNS
      WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'pay_product_term' AND COLUMN_NAME = 'file_path'
    ),
    'SELECT 1',
    'ALTER TABLE pay_product_term ADD COLUMN file_path varchar(500) DEFAULT NULL COMMENT ''这一版源文件OSS地址，oss://bucket/key'' AFTER effective_end'
  )
);
PREPARE stmt FROM @ddl;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;