The query optimizer might come up with a different query execution plan tailored to provide good performance for fast retrieval of first 'n' rows rather than all the result rows.
查询优化器可能得出一个不同的查询执行计划，这个计划可以专门为最快地获取前' N '行，而不是所有结果行提供良好的性能。
2
They made the board too shiny, reflecting the lights, and fidgeted and coughed until he cleared out the first seven rows of the audience.
他们使棋盘产生强烈的反光，他们不停的挪动和咳嗽，一直到鲍比·菲舍尔清除了前七排的观众为止。
3
This selects all the data from table for the first few rows.