在sqlite3中读回datetime [英] Reading back a datetime in sqlite3
问题描述
>>> db = sqlite3.connect(':memory:',detect_types = sqlite3.PARSE_DECLTYPES)
>>> c = db.cursor()
>>> c.execute('create table foo(bar integer,baz timestamp)')
< sqlite3.Cursor object at 0x7eff420e0be0>
>>> c.execute('insert into foo values(??)',(23,datetime.datetime.now()))
< sqlite3.Cursor对象在0x7eff420e0be0>
>>> c.execute('select * from foo')
< sqlite3.Cursor对象在0x7eff420e0be0>
>>> c.fetchall()
[(23,datetime.datetime(2010,12,14,1,15,54,685575))]
>>> c.execute('从foo'中选择max(baz)'
< sqlite3.Cursor对象在0x7eff420e0be0>
>>> c.fetchall()
[(u'2010-12-14 01:15:54.685575',)]
我尝试将结果转换为时间戳,但只返回一年:
>> > c.execute('select cast(max(baz)as timestamp)from foo')
< sqlite3.Cursor object at 0x7eff420e0be0>
>>> c.fetchall()
[(2010,)]
有没有办法获取一个适当的datetime对象,而不是在获取之后使用datetime.strptime()手动转换字符串?
你必须设置detect_types到sqlite.PARSE_COLNAMES并使用作为foo [timestamp]
像这样:
import sqlite3
import datetime
db = sqlite3.connect(':memory:',detect_types = sqlite3.PARSE_COLNAMES)
c = db.cursor()
c.execute('create table foo(bar integer,baz timestamp)')
c.execute('insert into foo values(?,)),(23,datetime.datetime.now()))
c.execute('insert into foo values(??)',(42,datetime.datetime.now()+ datetime.timedelta(-1))
c.execute('select bar,baz asts [timestamp]from foo')
print c.fetchall()
c.execute('select max(baz)asts [timestamp]from foo')
打印c.fetchall()
做了一个很好的Google搜索,发现这个消息。
I am using Python to create an in-memory sqlite3 database with a timestamp column. When I use min() or max() on this column in my query, the column is returned as a string rather than a Python datetime object. I read a previous question on Stackoverflow that provided a solution for normal SELECT statements, but it doesn't work if max() or min() is used. Here's an example:
>>> db = sqlite3.connect(':memory:', detect_types=sqlite3.PARSE_DECLTYPES)
>>> c = db.cursor()
>>> c.execute('create table foo (bar integer, baz timestamp)')
<sqlite3.Cursor object at 0x7eff420e0be0>
>>> c.execute('insert into foo values(?, ?)', (23, datetime.datetime.now()))
<sqlite3.Cursor object at 0x7eff420e0be0>
>>> c.execute('select * from foo')
<sqlite3.Cursor object at 0x7eff420e0be0>
>>> c.fetchall()
[(23, datetime.datetime(2010, 12, 14, 1, 15, 54, 685575))]
>>> c.execute('select max(baz) from foo')
<sqlite3.Cursor object at 0x7eff420e0be0>
>>> c.fetchall()
[(u'2010-12-14 01:15:54.685575',)]
I tried to cast the result to a timestamp but it only returns the year:
>>> c.execute('select cast(max(baz) as timestamp) from foo')
<sqlite3.Cursor object at 0x7eff420e0be0>
>>> c.fetchall()
[(2010,)]
Is there any way to fetch a proper datetime object, without manually converting the string using datetime.strptime() after fetching it?
You have to set detect_types to sqlite.PARSE_COLNAMES and use as "foo [timestamp]"
like this:
import sqlite3
import datetime
db = sqlite3.connect(':memory:', detect_types = sqlite3.PARSE_COLNAMES)
c = db.cursor()
c.execute('create table foo (bar integer, baz timestamp)')
c.execute('insert into foo values(?, ?)', (23, datetime.datetime.now()))
c.execute('insert into foo values(?, ?)', (42, datetime.datetime.now() + datetime.timedelta(-1)))
c.execute('select bar, baz as "ts [timestamp]" from foo')
print c.fetchall()
c.execute('select max(baz) as "ts [timestamp]" from foo')
print c.fetchall()
Did a nice little Google search and found this message.
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