-- prc_quote: product / cost amounts (run once on existing DB)
SET @col_exists := (
  SELECT COUNT(1) FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'prc_quote' AND COLUMN_NAME = 'product_amount'
);
SET @sql := IF(@col_exists = 0,
  CONCAT(
    'ALTER TABLE `prc_quote` ',
    'ADD COLUMN `product_amount` decimal(18,4) DEFAULT NULL COMMENT ''产品价合计'' AFTER `payable_total`, ',
    'ADD COLUMN `redline_amount` decimal(18,4) DEFAULT NULL COMMENT ''红线价合计'' AFTER `product_amount`, ',
    'ADD COLUMN `cost_amount` decimal(18,4) DEFAULT NULL COMMENT ''成本价合计（当前等于产品目录价）'' AFTER `redline_amount`, ',
    'ADD COLUMN `pay_total` decimal(18,4) DEFAULT NULL COMMENT ''应付合计（当前等于成本价）'' AFTER `cost_amount`'
  ),
  'SELECT 1');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;