What is the syntax to filter information from two different tables

Answer 1

well, try this
if both tables have some column names that are the same, then we can have

SELECT table1.column2, table2.column3 FROM table1, table2;

Answer 2

IF the both tables have something in common, you can use the join command and after that you can use any filter you would like to use.

Example:
select * from A join B on a.column = b.column where a.column = parameter;

thats one way to do it, now if both tables are have nothing in common, you have to use different querys.

Answer 3

yes if the child table has the foriegn key then you may use the concept of joining table, and then place the necessary filters using "where" command.