Using MapInfo SQL?

Question

I am trying to create a map of U.S. counties that shows migration patterns.

I have a table of all US counties and a table that has migration information.

Some counties do not have migration, hence when I match the counties by fips in the two data sets the counties that do not have migration are missing in the map.

How can I keep all the counties (in first table) even if not included in second table?

Answer 1

I would try using a LEFT JOIN.

SELECT
FROM Table_A A
LEFT JOIN Table_B B
ON A.Key = B.Key

Visual Representation of SQL Statemets

MapInfo Specific Tutorial on Joins