程序代码：

CREATE TABLE T (A I,B C(2),C C(3))
INSERT INTO T VALUES (1,[AA],[BB1])
INSERT INTO T VALUES (2,[AA],[BB2])
INSERT INTO T VALUES (3,[CC],[BB3])
INSERT INTO T VALUES (4,[AA],[BB4])
INSERT INTO T VALUES (5,[CC],[BB5])
INSERT INTO T VALUES (6,[BB],[BB6])
INSERT INTO T VALUES (7,[DD],[BB7])
* 1. 删除重复的记录行
SELECT * FROM T WHERE B IN (SELECT B FROM T GROUP BY B HAVING COUNT(B)=1) INTO ARRAY TT
SELECT T
ZAP
APPEND FROM ARRAY TT
BROWSE
* 2. 保留重复的记录行中的一条记录
* A. 保留 A 字段值最小的那条记录
SELECT * FROM T WHERE B IN (SELECT B FROM T GROUP BY B HAVING COUNT(B)=1) INTO ARRAY TT
DELETE FROM T WHERE  A NOT IN (SELECT MIN(A) FROM T GROUP BY B HAVING COUNT(B)>1)
SELECT T
PACK
APPEND FROM ARRAY TT
BROWSE
* B. 保留 A 字段值最大的那条记录
SELECT * FROM T WHERE B IN (SELECT B FROM T GROUP BY B HAVING COUNT(B)=1) INTO ARRAY TT
DELETE FROM T WHERE  A NOT IN (SELECT MAX(A) FROM T GROUP BY B HAVING COUNT(B)>1)
SELECT T
PACK
APPEND FROM ARRAY TT
BROWSE