I want to have Psycopg2 update col1, col2 and col3 when there is a conflict of id.

In my Python code I have the insert SQL currently as:

insert_sql = '''INSERT INTO {t} (id,col1,col2,col3)
        VALUES (%s,%s,NULLIF(%s, 'nan'), NULLIF(%s, 'nan'))
        ON CONFLICT (id)
        DO NOTHING;'''

Basically instead of DO NOTHING I want to set:

(col1,col2,col3) = (%s,NULLIF(%s, 'nan'), NULLIF(%s, 'nan'))

Which ignores inserting ID and updates col1, col2, and col3. The problem is using %s to pass in tuple variables in Python using Psycopg2:


What is the syntax used to refer to the %s corresponding to col1, col2, and col3 to update ON CONFLICT?

1 Answer 1


You can use the EXCLUDED keyword to access the values passed to INSERT. No need to pass them twice:

insert_sql = '''
   INSERT INTO {t} (id,col1, col2, col3)
        VALUES (%s, %s, NULLIF(%s, 'nan'), NULLIF(%s, 'nan'))
        ON CONFLICT (id)
            (col1, col2, col3)
            = (EXCLUDED.col1, EXCLUDED.col2, EXCLUDED.col3) ;

See examples of use in Postgres documentation about ON CONFLICT.

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