兼容性判定
真机验证：opengauss 6.0.5, gaussdb 505 · UPDATE 后 DELETE WHERE 组合子句待真库验证公开资料依据 · 建议 PoC 复核支持度partial
严重度major
置信度medium
依据规则ora.syntax.merge_update_delete
怎么改
需按命中位置逐条评估改写
判定说明
UPDATE 后 DELETE WHERE 组合子句待真库验证
库侧 / 应用侧路径
库侧改造
可行：对象内拆分为 MERGE 更新 + 后置 DELETE（作用于更新后值的范围显式收敛）
应用侧改造
可行：应用 SQL 同法拆分改写并回归
推荐路线：app_side。验证建议：构造“更新后满足删除条件”的用例——拆分改写与原子 MERGE 语义差异必测
规则样例
MERGE INTO t USING s ON (t.id = s.id) WHEN MATCHED THEN UPDATE SET t.qty = t.qty - s.qty DELETE WHERE t.qty <= 0
MERGE INTO stock USING d ON (stock.sku = d.sku) WHEN MATCHED THEN UPDATE SET cnt = d.cnt DELETE WHERE cnt = 0 WHEN NOT MATCHED THEN INSERT (sku, cnt) VALUES (d.sku, d.cnt)
MERGE INTO t USING s ON (t.id = s.id) WHEN MATCHED THEN UPDATE SET t.qty = s.qty