Python - Match most recent date prior to another date (SQL)

I am trying to match two dataframes using SQL in Python. I would like to match the most recent observation prior to a corresponding date on the other dataframe. So far, I have the following code, where I match all observations before the corresponding date (datadate).

In subsequent steps I create a variable that is the difference in days between filing_date and datadate, and then keep the observation with the least amount of days. However, this feels clunky and can present issues. Is there a way for me to do this within the SQL code? I would like to maintain all observations from datatable1. I included my current code and created tables below showing what I would like to do. Thanks for the help!

 import sqlite3
 sqlconn = sqlite3.connect(':memory:')
 datatable1.to_sql('datatable1',sqlconn, index=False)
 datatable2.to_sql('datatable2', sqlconn, index=False)

 qry = '''
SELECT DISTINCT
a.*, b.filing_date, b.value
FROM datatable1 AS A
LEFT JOIN datatable2 AS B
ON a.id = b.id AND b.filing_date < a.datadate
'''
compq_01 = pd.read_sql_query(qry, sqlconn)

datatable1:

datatable2:

What I want the resulting table to look like: