-- +goose Up

-- 为长期未关联上传归属记录的定时清理提供索引。
-- 兼容历史上已按旧编号执行过该索引的数据库，重复执行时跳过。
SET @idx_exists := (
  SELECT COUNT(*) FROM information_schema.statistics
  WHERE table_schema = DATABASE()
    AND table_name = 'file_upload_owners'
    AND index_name = 'idx_file_upload_owners_created_at'
);
SET @ddl := IF(@idx_exists > 0,
  'SELECT 1',
  'ALTER TABLE file_upload_owners ADD KEY idx_file_upload_owners_created_at (created_at)');
PREPARE stmt FROM @ddl;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

-- +goose Down

ALTER TABLE file_upload_owners
  DROP INDEX idx_file_upload_owners_created_at;