本文将详细介绍 DISTINCT 和 GROUP BY 的区别、适用场景以及它们对查询性能的影响。 在 SQL 查询中，DISTINCT 和 GROUP BY 是两个常见的用于去重和分组的操作符。然而，尽管它们在某些情况下可以达到相同的效果，但它们在原理、适用场景和性能方面却有很大的不同。

Do you want to find out how to avoid duplicates in the results of a SQL SELECT query? This article will show you how. Simply use the DISTINCT clause and between the SELECT clause and the fields.

fMRI changes are typically assumed to be due to changes in neural activity, although whether this remains valid under the influence of neuromodulators is relatively unknown. Here, we found evidence ...

Inside a PROC SQL statement, syntax changes. Docuwiki's syntax highlighting should reflect this. Problem code: the asterisk in the select statement is treated as a SAS comment. proc sql; select count( ...