postgresql 如何在postgresql选择查询中仅从age()函数中获取年份
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时间：2020-10-21 02:26:18 来源:igfitidea点击:
How to get only year from age() function in postgresql select query
提问by Vikrant
The following query returns:
以下查询返回：
SELECT AGE(cast(dob AS date))
FROM mas_patient_details;
age
----------
39 years 5 mons 19 days
13 years 2 days
69 years 2 days
41 years 11 mons 25 days
This query returns:
此查询返回：
SELECT age(cast(dob as date))
FROM mas_patient_details
WHERE age <= 59;
age
----------
39 years 5 mons 19 days
13 years 2 days
69 years 2 days
41 years 11 mons 25
How would one extract simply the year from one of these queries?
如何从这些查询之一中简单地提取年份？
回答by Vikrant
If column fu is of data type DATE, you could use
如果列 fu 的数据类型为 DATE，则可以使用
SELECT EXTRACT(YEAR FROM fu) FROM mydate;
and if it is varchar, you convert it to date using to_date()
如果是 varchar，则使用 to_date() 将其转换为日期
SELECT EXTRACT(YEAR FROM to_date(fu, <your pattern>)) FROM mydate;
In your case:
在你的情况下：
select EXTRACT(YEAR FROM age(cast(dob as date)))
from mas_patient_details
where age <= 59;
