SQL interval join 问题

现有 SQL 语句如下： create table source1( id varchar PRIMARY KEY, a varchar, proctime AS PROCTIME() ) with ( 'connector' = 'kafka' ... ); create table source2( id varchar PRIMARY KEY, a varchar, proctime AS PROCTIME() ) with ( 'connector' = 'kafka' ... ); select case when s1.id is not null then s1.id else s2.id end as ids, s1.a, s2.b from source1 as s1 full outer join source2 as s2 on s1.id = s2.id where s1.proctime between s2.proctime - INTERVAL '5' SECOND and s2.proctime + INTERVAL '5' SECOND;

最后的 join 语句预期是 如果两个source的消息<id, a>, <id, b>先后到达时间超过 10 秒，则输出<id, a>, <id, b> 两条消息。

目前的观察结果是，如果两条消息<id, a>, <id, b>先后到达时间超过10 秒，输出为：<id, a>, <id, a, b> 为何超过 10 秒后，仍然会输出 <id, a, b> ？*来自志愿者整理的flink