Why %time output is Wall time: 0 ns in Jupyter Notebook with IPython?

I try to measure query speed in my jupyter notbook

%time
a10= pd.read_sql('SELECT t.id, t.order_id FROM transactions.t', con=db_connection)

Whatever my query is the output always

Wall time: 0 ns

I assume %time is not related with previous cell, this cell requires more than 10s to execute, why Wall time: 0 ns ?