CAST（DATETIME AS DATE）over WHERE子句 [英] CAST(DATETIME AS DATE) over WHERE clause

问题描述

我使用的是SQL Server 2012，我想知道我是否写了句子：

I'm using SQL Server 2012 and I would like to know if I write the sentence:

SELECT MyDateTimeColumn 
FROM MyTable
WHERE CAST(MyDateTimeColumn AS DATE) = '2014-07-09'

是一个较慢的方式来修剪DATETIME列的时间，我已经搜索，但我找不到任何关于这个严格的句子，我不知道如何显示关于耗时的impresive统计数据转换/探测它自己。

is a slower way to trim the time over DATETIME columns, I have searched but I can't find anything about this strict sentence and I don't know how to show that impresive statistics about time consuming cast/convert to probe it myself.

推荐答案

在SQL 2008+， CAST（foo AS date）是可吞噬的，以及一些其他的操作。查看sqlfiddle中的执行计划。

In SQL 2008+, CAST(foo AS date) is sargable, along with a few other manipulations. Look at the execution plans in the sqlfiddle.

SQL谜语示范

SQL Fiddle Demo

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