VFP中比较两个表，查看一个表中多的人员是谁，表中数据很多，有两万条，有没有办法提高校核速度？
打个比方，有两个人员表，分别是ry1 字段为姓名xm c(10),身份证号sfzh c(20),20000条数据;ry2 字段为姓名，xm c(10),身份证号sfzh c(20)，20001条数据，两个表中身份证号唯一，现在要比对出ry2表中多的人是谁，我用以下程序，速度太慢，得半小时才能出结果。
set talk off
use ry2
for i=1 to recc()
sele sfzh from ry1 into array r_1 wher recn()=i
use ry1
loca for sfzh=r_1
if not found()
?r_1
endif
endfor

select * from ry2 where sfzh not in (select sfzh from ry1)

或者
select sfzh from ry2 into array ary2
select sfzh from ry1 into array ary1
用 ascan()搜索

SELECT ry1
INDEX on sfzh TAG t_sfzh
SELECT ry2
SET RELATION TO sfzh INTO "ry1"
SCAN FOR ry2.sfzh != ry1.sfzh
    ? ry2.xm,ry2.sfzh
ENDSCAN

如果只想查看 select * from ry2 into cursor dyry where !(sfzh in (select distinct sfzh from ry1))
若想保留结果 select * from ry2 into dbf dyry where !(sfzh in (select distinct sfzh from ry1))

这个表述真有点难懂

SELECT ry1
INDEX on sfzh TAG t_sfzh
SELECT ry2
SET RELATION TO sfzh INTO "ry1"
brow for empty(ry1.t_sfzh)
* 借用楼上的现成语句，我其实只写了最后一句。
* brow 浏览内容将只包含你想看到的！估计5以内就出结果了。
* 也可以复制出来：copy to xxx for empty(ry1.t_sfzh)

也可以用sele -left join，然后brow for empty(ry1.t_sfzh)

SELECT ry1
INDEX on sfzh TAG t_sfzh
SELECT ry2
SET RELATION TO sfzh INTO "ry1"
brow for sfzh#ry1.sfzh
我也改最后一句