SET @index_exists := (
  SELECT COUNT(1)
  FROM information_schema.statistics
  WHERE table_schema = DATABASE()
    AND table_name = 'payment_methods'
    AND index_name = 'uq_payment_methods_company_system_key'
);

SET @drop_index_sql := IF(
  @index_exists > 0,
  'DROP INDEX `uq_payment_methods_company_system_key` ON `payment_methods`',
  'SELECT 1'
);

PREPARE stmt FROM @drop_index_sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

SET @column_exists := (
  SELECT COUNT(1)
  FROM information_schema.columns
  WHERE table_schema = DATABASE()
    AND table_name = 'payment_methods'
    AND column_name = 'system_key'
);

SET @drop_column_sql := IF(
  @column_exists > 0,
  'ALTER TABLE `payment_methods` DROP COLUMN `system_key`',
  'SELECT 1'
);

PREPARE stmt FROM @drop_column_sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;