| Interval Join | 两条流按事件时间区间匹配，如订单与支付 15 分钟内关联 |
|---|---|
| Lookup Join | 流去外部维表点查，适合缓慢变化维 |
| 状态成本 | interval join 需保存区间内两侧数据 |
Flink SQL 维表关联
Flink SQL 维表关联
SELECT o.order_id, u.city
FROM orders AS o
JOIN user_dim FOR SYSTEM_TIME AS OF o.proc_time AS u
ON o.user_id = u.user_id;Flink SQL 区间关联
Flink SQL 区间关联
SELECT o.order_id, pay.pay_id
FROM orders o JOIN payments pay
ON o.order_id = pay.order_id
AND pay.pay_time BETWEEN o.order_time AND o.order_time + INTERVAL '15' MINUTE;lookup join 的维表缓存过期时间决定数据新鲜度，调大缓存能减压力但会命中旧维度值。