SELECT * from Plan INTO CURSOR crsPlan readwrite

nMin = 10
nMax = 20

FOR ix = 1 TO nMin - 1
lcName = 'G' + ALLTRIM(STR(ix))

ALTER TABLE crsTemp ;
DROP (lcName)
ENDFOR

FOR ix = nMax + 1 TO 200 && Because of your sample is G200.
lcName = 'G' + ALLTRIM(STR(ix))

ALTER TABLE crsTemp ;
DROP (lcName)
ENDFOR