Hi,

FULL JOIN is a symmetric join,
then

 ... T1 FULL JOIN T2 ....
* is equal to
 ... T2 FULL JOIN T1 ....

On VFP this is not true:
Example 1 ( test symmetric )

CREATE CURSOR T1 (F1 I )
CREATE CURSOR T2 (F2 I )
INSERT INTO T1 VALUES (1)
INSERT INTO T2 VALUES (2)
SELECT * FROM T1 FULL JOIN T2 ON .T.
* ---------
*   1     2
* NULL    2  this is bad records
SELECT * FROM T2 FULL JOIN T1 ON .T.
* ---------
*   2     1
* NULL    1 this is bad records

Example 2
( asymmetry with cardinal loop optimization -> result change )

CREATE CURSOR T1 (F1 I )
CREATE CURSOR T2 (F2 I )
INSERT INTO T1 VALUES (1)
INSERT INTO T2 VALUES (2)
SELECT F1,F2 FROM T1 FULL JOIN T2 ON .T.
* -F1---F2--
*   1     2
* NULL    2  nulls are on F1 fields

&& next force VFP to change loop join pivot to T2
INSERT INTO T1 VALUES (3) ble

SELECT F1,F2 FROM T1 FULL JOIN T2 ON .T.
* -F1---F2--
*   1     2
*   3     2
*   1    NULL null are on F2 fields
*   3    NULL null are on F2 fields

* if i force pivot looping to T1, result is obvious now
SELECT F1,F2 FROM FORCE T1 FULL JOIN T2 ON .T.
* -F1---F2--
*   1     2
*   3     2
* NULL    2  nulls are on F1 fields

With 3 tables results is more clear:

CREATE CURSOR T1 (F1 I )
CREATE CURSOR T2 (F2 I )
CREATE CURSOR T3 (F3 I )
INSERT INTO T1 VALUES (1)
INSERT INTO T2 VALUES (2)
INSERT INTO T3 VALUES (3)
SELECT F1,F2,F3 FROM T1 FULL JOIN T2 ON .T. FULL JOIN T3 ON .T.
* 4 Records

INSERT INTO T1 VALUES (3) && this force VFP to change loop join pivot table

SELECT F1,F2,F3 FROM T1 FULL JOIN T2 ON .T. FULL JOIN T3 ON .T.
*  8 records

SELECT F1,F2,F3 FROM FORCE T1 FULL JOIN T2 ON .T. FULL JOIN T3 ON .T.
*  4 records

If this is by design, then it is very different of SQL Server FULL JOIN.

Fabio