更新 python 中的 postgres 表列值？

Question

I have one offset date to be stored in Postgres table -

latest_mod_date = max(data['last_modified'])

latest mod_date = 2022-04-16 05:50:00 

Want this date to be updated in postgres -

Used this query - The postgres table data_offset is like this -

_id offset_type offset_value    
    1     C          [NULL] 
    2     P          [NULL] 


# # query to update - global is the schema and data_offset is the data table in postgres

sql = '''update global.data_offset set {offset_value=latest_mod_date} where {offset_type='C'}; '''
#
# # execute the query
cursor.execute(sql)
print("Table updated..")

print('Table after updation...')

# query to display table
sql2 = 'select * from global.data_offset;'

# execute query
cursor.execute(sql2);

# fetching all details
print(cursor.fetchall());

This query is giving error -

psycopg2.errors.SyntaxError: syntax error at or near "{"
LINE 1: update global.data_offset set {offset_value=latest_mo...

I want the latest_mod_date to be stored in the offset value where the offset_stypr is 'C'.

Answer 1

Any place you have seem {} is probably because people have been doing something like sql_str.format() which is the wrong thing to do. See Parameter passing for the correct way to pass variables in.

In your case what you need is:

sql = "update global.data_offset set offset_value = %s where offset_type='C'"

cursor.execute(sql, [latest_mod_date])

# Commit the changes.
con.commit()