In the case of the UnionExpression class, the evaluate method evaluates the two operands, checks that the result is in both cases a node-set, and then forms the union using a sort-merge strategy.

如果是unionexpression类，evaluate方法将对两个操作数求值，检查在这两种情况下节点集的结果，然后使用排序合并策略组成联合。

youdao

Join plan directives that force optimizer to use the designated join method to join tables in the query, either nested loop join, sort merge join, or dynamic hash join.

连接计划指示，强制优化器使用指定的连接方法来连接查询中的表，要么是嵌套循环连接、分类合并连接，要么是动态哈希连接。

youdao

Also, DB2 cannot use random order index columns as part of a sort merge join.

另外，DB 2无法在排序合并合并连接中使用随机顺序的索引列。

youdao

- So again, if you're unwinding what's going on here, this-- we sorted the left half which meant sort the left half, then the right half then the merge.

同样，如果你展开正在进行的一切-,我们已对左半部分排好了序，接着右半部分，接着合并。

哈佛公开课 - 计算机科学课程节选

Just to prove that his atoms really were acting as single waves, Dr Ketterle made two condensates at the same time, and allowed them to merge, thus creating ripple-like interference patterns of the sort that might be seen if two stones were thrown simultaneously into the same pond.

ECONOMIST: The 2001 Nobel prizes: Playing catch-up | The