oracle 如何选择超过 12 个月的数据？
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How to select data that is older than 12 months?
提问by Stacker-flow
I have a table as follows;
我有一张表如下；
caravan_id, description, date_purchased, special_instructions, health&safety_check, notes
health&safety_checkis a date field.
health&safety_check是一个日期字段。
How can I perform an SQL query for data in this table that returns all rows which have a health&safety_checkolder than 12 months. But if possible one that is based on 12 months, not on today's date such as < 10/12/2011
如何对该表中的数据执行 SQL 查询，以返回health&safety_check超过 12 个月的所有行。但如果可能的话，基于 12 个月的日期，而不是今天的日期，例如 < 10/12/2011
回答by Gordon Linoff
Something like:
就像是：
select *
from t
where add_months("health&safety_check", 12) < sysdate
I assume you don't want to hardcodethe current date but are happy with using a variable for it.
我假设您不想对当前日期进行硬编码，但对使用变量感到满意。
Jeff, in the comments, makes a good point (although, in Oracle, you can create an index on a function so you can get around the problem). This is easily fixed:
Jeff 在评论中提出了一个很好的观点（尽管在 Oracle 中，您可以在函数上创建索引，以便解决问题）。这很容易解决：
where "health&safety_check" <add_months(sysdate, -12)
回答by Jeffrey Kemp
select *
from t
where "health&safety_check" < add_months(sysdate, -12)
回答by Reinstar
You can use this query:
您可以使用此查询：
SELECT *
FROM table_name
WHERE `health&safety_check` < ADDDATE(NOW(), INTERVAL -12 MONTH)
ADDDATE(NOW(), INTERVAL -12 MONTH) mean this date minus 12 Month, you can use other date field or variable to change NOW().
ADDDATE(NOW(), INTERVAL -12 MONTH) 表示该日期减去 12 个月，您可以使用其他日期字段或变量来更改 NOW()。
NOW() mean today.
NOW() 表示今天。
