-- Run once against an existing planning MySQL/MariaDB database before deployment.
SET @sku_fingerprint_exists = (
  SELECT COUNT(*)
  FROM information_schema.columns
  WHERE table_schema = DATABASE()
    AND table_name = 'alibaba_1688_products'
    AND column_name = 'sku_fingerprint'
);
SET @add_sku_fingerprint_sql = IF(
  @sku_fingerprint_exists = 0,
  'ALTER TABLE alibaba_1688_products ADD COLUMN sku_fingerprint CHAR(64) NULL COMMENT ''有序 SKU 规格指纹'' AFTER sku_count',
  'SELECT 1'
);
PREPARE add_sku_fingerprint_stmt FROM @add_sku_fingerprint_sql;
EXECUTE add_sku_fingerprint_stmt;
DEALLOCATE PREPARE add_sku_fingerprint_stmt;