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up vote -1 down vote favorite

I am tying to insert null value to a postgres timestamp datatype variable using python psycopg2.

The problem is the other data types such as char or int takes None, whereas the timestamp variable does not recognize None.

I tried to insert Null , null as a string because I am using a dictionary to get append the values for insert statement.

Below is the code.

queryDictOrdered[column] = queryDictOrdered[column] if isNull(queryDictOrdered[column]) is False else NULL

and the function is 

def isNull(key):
    if str(key).lower() in ('null','n.a','none'):
        return True
    else:
        False

I get the below error messages:

DataError: invalid input syntax for type timestamp: "NULL"
DataError: invalid input syntax for type timestamp: "None"

share|improve this question
up vote 0 down vote

Surely you are adding quotes around the placeholder. Read psycopg documentation about passing parameters to queries.

share|improve this answer
    
the quotes around the null is to check the values before inserting !!! If you see the first piece of code I am trying to insert a NULL but since i am adding to a dictionary and then inserting the value I am not able to add NULL as a place holder but a string. So I need a work around to add null !! – Subu Ganesh Feb 22 at 20:26
    
use: queryDictOrdered[column] = queryDictOrdered[column] if not isNull(queryDictOrdered[column]) else None – piro Feb 23 at 10:55
    
You can insert None to Varchar variables but unfortunately, you cannot insert None to postgressql datetime variable. That is where I am having issues. I have found a work around of inserting dummy dates eg: '9999-12-12' but still not sure of how to insert null value :( – Subu Ganesh Feb 23 at 16:03
    
You are wrong: you can insert NULL to any Postgres data type, including dates and timestamps, and you can do that passing a None in psycopg. – piro Feb 23 at 16:14

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