我用大量数据绘制了表格。 让我们说10种大体线,包括一刀切。 例如,我需要选择X浏览(X通常低于10)和最高<代码>amount栏。
是否在不分整个表格的情况下这样做? 提供这一数据是极具成本效益的,因此,我是大韩民国,整个表格中有一个扫描器,选择X最高数值,并允许其余数据。 I m使用服务器。
建立<代码>amount的索引 然后,服务器可以从中选取top 10,并用书记眼检索缺失的栏目。
SELECT TOP 10 Amount FROM myTable ORDER BY Amount DESC
if it is indexed, the query optimizer should use the index.
If not, I do no see how one could avoid scanning the whole thing...
Wether an index is usefull or not depends on how often you do that search.
You could also consider putting that query into an indexed view. I think this will give you the best benefit/cost ration.
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