尝试查找不同数据时返回相同的结果

Posted 2023-04-18

【中文标题】尝试查找不同数据时返回相同的结果

【英文标题】：Get back the same result when trying to find different data

【发布时间】：2012-08-15 02:59:10

【问题描述】：

我可以从下面的查询中获取每年的15/02 - 21/06 日期范围数据。

SELECT * FROM dim_date
WHERE EXTRACT (MONTH FROM date_cal) BETWEEN 3 AND 5
 OR (EXTRACT (MONTH FROM date_cal) = 2 AND EXTRACT (DAY FROM date_cal) >= 15)
 OR (EXTRACT (MONTH FROM date_cal) = 6 AND EXTRACT (DAY FROM date_cal) <= 21)

但问题是，当我想从年份2010 - 2012 中查找时，我得到了相同的结果。

我想得到的范围：

2010-02-15 - 2010-06-15
2011-02-15 - 2011-06-15
2012-02-15 - 2012-06-15

SELECT * FROM dim_date
WHERE EXTRACT (MONTH FROM date_cal) BETWEEN 3 AND 5
 OR (EXTRACT (MONTH FROM date_cal) = 2 AND EXTRACT (DAY FROM date_cal) >= 15)
 OR (EXTRACT (MONTH FROM date_cal) = 6 AND EXTRACT (DAY FROM date_cal) <= 21)
AND EXTRACT (YEAR FROM date_cal) BETWEEN 2010 AND 2012

谁能帮我解决这个问题！

【问题讨论】：

考虑follow-up question with more answers。还有this related question with much more on the topic.

【参考方案1】：

您的问题是缺少括号：在 SQL 中，AND 优先于 OR，因此您需要将括号括在前面的整个表达式中：

SELECT * FROM dim_date
WHERE ( -- added bracket
 EXTRACT (MONTH FROM date_cal) BETWEEN 3 AND 5
 OR (EXTRACT (MONTH FROM date_cal) = 2 AND EXTRACT (DAY FROM date_cal) >= 15)
 OR (EXTRACT (MONTH FROM date_cal) = 6 AND EXTRACT (DAY FROM date_cal) <= 21)
 ) -- added bracket
AND EXTRACT (YEAR FROM date_cal) BETWEEN 2010 AND 2012

没有括号，你得到A or B or (C and D)，但你想要(A or B or C) and D