查询比较SQL中的日期 [英] Query comparing dates in SQL

问题描述

我有一个表格，日期都发生在11月。
我写了此查询

 从Test_Table $ b中选择id，numbers_from，created_date，amount_numbers，SMS_text 
 $ b其中
 created_date< ='2013-04-12'
  

返回在第11（11月）发生的一切，因为之前日期'2013-04-12'（12月）

它只会返回小于04的日期发生的可用日期（2013- 04 -12）

这可能是因为它只比较日期部分？

Created_date类型日期

/ strong>

日期格式为默认 yyyy-dd-MM

解决方案

取代2013-04-12，其含义取决于当地文化，使用被识别为文化不变格式的20130412。

如果您想与12月4日 ^th 进行比较，您应该写20131204。如果你想与4月12日 ^th 比较，你应该写'20130412'。

文章写国际Transact-SQL语句说明如何编写文化不变的语句：

使用其他API或Transact-SQL脚本，存储过程和触发器的应用程序应使用未分隔的数字字符串。例如，yyyymmdd为19980924.

EDIT

由于您使用ADO，最好的选项是参数化查询，并将日期值作为日期参数传递。这样，您就可以完全避免格式问题，并获得参数化查询的性能优势。

UPDATE

要在文字中使用ISO 8601格式，必须指定所有元素。引用从datetime文档的ISO 8601部分

要使用ISO 8601格式，必须以格式指定每个元素。这也包括以格式显示的T，冒号（:)和句点（。）。

...第二个组件的分数是可选的。时间组件以24小时格式指定。

I have a table with dates that all happened in the month November. I wrote this query

select id,numbers_from,created_date,amount_numbers,SMS_text 
from Test_Table
where 
created_date <= '2013-04-12'

This query should return everything that happened in month 11 (November) because it happened before the date '2013-04-12' (in December)

But it's only returning available dates that happened in days lesser than 04 (2013-04-12)

Could it be that it's only comparing the day part? and not the whole date?

How to fix this?

Created_date is of type date

Date format is by default yyyy-dd-MM

解决方案

Instead of '2013-04-12' whose meaning depends on the local culture, use '20130412' which is recognized as the culture invariant format.

If you want to compare with December 4^th, you should write '20131204'. If you want to compare with April 12^th, you should write '20130412'.

The article Write International Transact-SQL Statements from SQL Server's documentation explains how to write statements that are culture invariant:

Applications that use other APIs, or Transact-SQL scripts, stored procedures, and triggers, should use the unseparated numeric strings. For example, yyyymmdd as 19980924.

EDIT

Since you are using ADO, the best option is to parameterize the query and pass the date value as a date parameter. This way you avoid the format issue entirely and gain the performance benefits of parameterized queries as well.

UPDATE

To use the the the ISO 8601 format in a literal, all elements must be specified. To quote from the ISO 8601 section of datetime's documentation

To use the ISO 8601 format, you must specify each element in the format. This also includes the T, the colons (:), and the period (.) that are shown in the format.

... the fraction of second component is optional. The time component is specified in the 24-hour format.

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