在EXTRACT中转换时出现语法错误

Question

我只是试试这个，我的tdate语法错误（它是DATE类型）

select *
from treatment
where  EXTRACT(month FROM cast (date as TIMESTAMP) tdate) = EXTRACT(month FROM cast (date as TIMESTAMP) current_date)

有人可以帮帮我.. ?? 感谢!!!!

Answer 1

这是你要找的东西：

select *
from treatment
where EXTRACT(month FROM cast (tdate as TIMESTAMP)) = 
      EXTRACT(month FROM cast (current_date as TIMESTAMP))

cast(field as type)应该是cast(date as type)。

Answer 2

我不认为你需要打扰任何一个字段，因为你应该能够直接从两者中提取月份。我会尝试：

select * 
from treatment 
where extract(month from tdate) = extract(month from current_date)