如何在SQL查询中选择时间戳的一部分 [英] How to select part of a Timestamp in a SQL Query

问题描述

在正在使用的数据库中，我只想从特定的时间戳记"字段中选择年份.特别是，我希望从此数据库列中选择唯一年份.

In the DB I am working with, I want to select only the year from a specific TimeStamp field. In particular, I'm hoping to select the unique years from this database column.

例如，如果"ModifyTimeStamp"字段中的所有时间戳记都来自2002年或2006年，那么我只想返回"2002"和"2006"的结果.如果这不可能，那么我会满意地得到一堆'2002'和'2006'的混合结果，并在以后进行解析.

For instance, if all of the timestamps in the field "ModifyTimeStamp" are either from the year 2002 or the year 2006, I would like returned simply a result of '2002' and '2006'. If this is impossible, I'd be content with getting a result of a bunch of '2002's mixed with '2006's and would parse it later.

到目前为止，我只能进行的工作是"Select ModifyTimeStamp from Table"-我所有的解析尝试都失败了.我开始阅读有关SQL的extract命令的信息，但我相信它仅适用于PostgreSQL.

All I've been able to get working so far is "Select ModifyTimeStamp from Table" - all my attempts to parse have failed. I started reading about the extract command for SQL, but I believe it's only for PostgreSQL.

任何建议，不胜感激！

编辑:得到了答案，非常感谢datagod和Marc.我一直在寻找的代码最终是:

Edit: Got the answer, thanks a lot datagod and Marc. The code I was looking for ended up being:

"Select distinct YEAR(ModifyTimeStamp) from Table"

推荐答案

您没有指定要使用的RDBMS(数据库服务器)，但是大多数数据库确实具有内置的日期处理功能:

You don't specify which RDBMS (database server) you're using, but most databases do have date handling functions built-in:

• MySQL/SQL Server:

• MySQL/SQL Server:

select YEAR(modifytimestamp) from yourtable

Access/SQL Server:

Access/SQL Server:

select DatePart(year, modifytimestamp) from yourtable

Oracle:

Oracle:

select TO_CHAR(modifytimestamp, 'YYYY') from yourtable

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