sqlite3日期和间隔函数

Question

我想知道sqlite3是否支持间隔功能。 PostgreSQL接受以下语句，但是sqlite3无法解析它;

select
 ...
from 
 orders
where
 ...
 and o_orderdate < date '1995-03-01' + interval '3' month 

错误：靠近第4行：靠近“'1995-03-01'”：语法错误

然后，我修改了一些语句，如;

and o_orderdate < date('1995-03-01') + interval '3' month

这次错误是; 错误：靠近第4行：靠近“'3'”：语法错误

不幸的是，同样的技巧对区间函数不起作用，即

and o_orderdate < date('1995-03-01') + interval('3' month)

或

and o_orderdate < date('1995-03-01') + interval('3') month

甚至

and o_orderdate < date('1995-03-01') + interval(3 month)

仍然给了我语法错误。

也许sqlite3不支持间隔功能或我在使用中遗漏了什么？

非常感谢

Answer 1

and o_orderdate < date('1995-03-01', '+3 month')

reference of date and time functions in SQLite

Answer 2

try this:

and date(o_orderdate) < date('1995-03-01','+3 month')

In order to calculate dates, you must inform to SQLite that your database field is a date: date(o_orderdate)

SQLite syntax is pretty unflexible, so it's important to make sure that the + sign has no spaces to the following number: '+3 month'