Oops, had it backwards...

IF(COUNTA(A1:B1)=2,"ok",TRIM(IF(B1="","add client","") & IF(A1="",
"_add order", "")))


where _ is substituted for a space character to avoid unfortunate
linewrap.

In article ,
JE McGimpsey wrote:

=IF(COUNTA(A1:B1)=0,"ok",TRIM(IF(B1="","","add client") &
IF(A1="",""," add order")))