SQL Query to Join Two Tables Based Off Closest Timestamp

Question

I have two tables in SQL and I need to be able to do a join based off of the timestamp in table B that is earlier than or equal to the timestamp in table A.

So, here

Answer 1

change the time stamp and use an int as a key to connect the tables. this will work much faster then comparing date

table 1 field1 field2 field3 ConnectorField

table2 field1 field2 field3 ConnectorField

and all you need to do is select * from table1 T1 inner join table2 T2 on T1.ConnectorField = T2.ConnectorField