Dear all,

 

I have problems with iif function using sqldf library.

I counted abundance (Num) of different "SPECIES" in two moments (esf) saving
the information in two Tables (esf50, esf100):

esf50

SAMPLE      SPECIES      Num             esf

1289            diso1           44                  50

1289            diso2           5                     50

1289            diso3           1                     50

9999            diso1           44                  50

9999            diso2           5                     50

9999            diso3           1                     50

                                                                       

esf100                                

SAMPLE      SPECIES      Num             esf

1289            diso1           82                  100

1289            diso2           13                  100

1289            diso3           2                     100

1289            diso4           3                     100

9999            diso1           82                  100

9999            diso2           13                  100

9999            diso3           2                     100

9999            diso4           3                     100

 

I would like subtract column "Num" between the two moments considering only
the changes, therefore I use the conditional if:

 

var100<-sqldf("select esf100.SAMPLE, esf100.SPECIES, esf100.Num, esf100.esf,

                   iif esf100.Num - esf50.Num >=0, esf100.Num-esf50.Num,
esf100.Num as PIPAS 

                   from esf100 left join esf50 on esf100.SAMPLE =
esf50.SAMPLE

                   and esf100.SPECIES = esf50.SPECIES")

 

I think the structure is right because the SQL query run ok in Access. Is
the if syntax the problems?

 

Thank in advanced.

 

Best wishes,

 

Carlos Rivera

 

 

 

 


	[[alternative HTML version deleted]]

