-- +goose Up
SET @has_col := (
  SELECT COUNT(*)
  FROM information_schema.columns
  WHERE table_schema = DATABASE()
    AND table_name = 'flight_data'
    AND column_name = 'pilot_id'
);
SET @sql := IF(
  @has_col = 1,
  'ALTER TABLE flight_data MODIFY COLUMN pilot_id BINARY(16) NULL',
  'SELECT 1'
);
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

-- +goose Down
SET @has_col := (
  SELECT COUNT(*)
  FROM information_schema.columns
  WHERE table_schema = DATABASE()
    AND table_name = 'flight_data'
    AND column_name = 'pilot_id'
);
SET @sql := IF(
  @has_col = 1,
  'ALTER TABLE flight_data MODIFY COLUMN pilot_id BINARY(16) NOT NULL',
  'SELECT 1'
);
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;