Python + sqlalchemy: how to process timedelta on database side?

Question

Coding with Python, I want to insert time processed on the database side like this:

time = func.now()-datetime.timedelta(days=100)

or

time = func.current_timestamp()-datetime.timedelta(days=100)

but somehow it couldn't get through, seeing warning:

sqlalchemy\engine\default.py:330: Warning: Truncated incorrect DOUBLE value: '1970-01-04 00:00:00'

Any way to get it straight? thanks.

================================

I want to update a TIMESTAMP column 'date_buy' in table 'Purchase', an d instead of using datetime.datetime.now() to get the update time in python, I want to get this done in the database, meaning I would prefer func.now():

time = func.current_timestamp()-datetime.timedelta(days=100)
# time = datetime.datetime.now()-datetime.timedelta(days=100)
session.execute(update(Purchase).values(date_buy=time).where(Purchase.c.id == 11))

=================================

solved. thanks to Bryan and his post: http://groups.google.com/group/sqlalchemy/browse_thread/thread/a67d4f179e01b98a/ee688a0b8a999f52?hl=en&lnk=gst&q=date_add#ee688a0b8a999f52

If you found the solution then accept the answer to close the question. Please do this to complete the workflow of the system. — NPatel
– NPatel, Commented Feb 9, 2012 at 5:07

NPatel · Accepted Answer · 2012-02-08 04:22:41Z

2

The Warning is

Warning: Truncated incorrect DOUBLE value: '1970-01-04 00:00:00'

Means its truncating your data. Please check your field type in which you are going to store the time object. It says that you are trying to store DOUBLE value with datetime value.

If this will not solve the problem then just give some code example so we will get idea what you are going to do.

answered Feb 8, 2012 at 4:22

NPatel

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3 Comments

avemax Over a year ago

pls take a look at the edited post. i am not sure if this is a right way to leave the operation on that field to MySQL, not python. thanks!

NPatel Over a year ago

What is the type of date_buy? Please provide the class of Purchase.

NPatel Over a year ago

CURRENTTIMESTAMP is double value and you are trying to minus datetime from CURRENTTIMESTAMP. Just use same type of operand to perform the operation. You can use converttimestamp(func.now() - datetime.timedelta(days=100))

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