Hello,
I have this dataset, and I want to divide CLMS18/CLMS17 if NPI17 is the same as NPI18 and the gnrc17 is the same as gnrc18. Is there a command that can do that?
Thank you,

Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input long NPI17 str30 gnrc17 int CLMS17 long NPI18 str30 gnrc18 long CLMS18
1457350522 "Acetylcysteine"                  16 1356409437 "ACETYLCYSTEINE"                 20
1891993317 "Albuterol Sulfate"               23 1174904106 "ALBUTEROL SULFATE"              32
1851371405 "Amoxapine"                      104 1184003089 "ALBUTEROL SULFATE"              12
1417051921 "Amoxicillin/Potassium Clav"      44 1063674364 "ALBUTEROL SULFATE"              12
1225023872 "Atenolol"                        55 1427293901 "AMOXICILLIN/POTASSIUM CLAV"     27
1700958659 "Atenolol/Chlorthalidone"         12 1609801380 "ATENOLOL/CHLORTHALIDONE"        16
1194753186 "Atropine Sulfate"                26 1588603781 "BUSPIRONE HCL"                  94
1952310666 "Buspirone Hcl"                   15 1043237613 "BUSPIRONE HCL"                 106
1225023872 "Carbidopa/Levodopa"              26 1447540349 "BUSPIRONE HCL"                  11
1104267053 "Cefpodoxime Proxetil"            11 1972849834 "CIPROFLOXACIN HCL"              74
1417967118 "Ceftazidime In Dextrose5%water"  14 1528118510 "CIPROFLOXACIN HCL"              19
1154588531 "Chorionic Gonadotropin, Human"   40 1669727822 "CIPROFLOXACIN HCL"              22
1538187000 "Ciprofloxacin"                   11 1851485049 "CIPROFLOXACIN HCL"              14
1225023872 "Clonidine Hcl"                   19 1326391707 "CIPROFLOXACIN HCL"              16
1225023872 "Cyclosporine"                    15 1215042866 "CYCLOSPORINE"                   14
1558542209 "Cytarabine/Pf"                   29 1861462772 "DORZOLAMIDE HCL"                37
1265497366 "Disopyramide Phosphate"          11 1245348911 "DORZOLAMIDE HCL"                22
1194753186 "Dorzolamide Hcl"                 16 1326070020 "DORZOLAMIDE HCL"                11
1023006913 "Fentanyl Citrate/Pf"             41 1417937715 "FLUDROCORTISONE ACETATE"        13
1700958659 "Fludrocortisone Acetate"         12 1730184540 "FLUDROCORTISONE ACETATE"        20
1952310666 "Fluphenazine Hcl"                33 1326159385 "FLUPHENAZINE HCL"               20
1316155864 "Flurbiprofen Sodium"            115 1376734806 "FUROSEMIDE"                     62
1801093968 "Furosemide"                      11 1134668890 "FUROSEMIDE"                     11
1194753186 "Gentamicin Sulfate"              22 1922090570 "FUROSEMIDE"                     51
1356326136 "Gentamicin Sulfate/Pf"           12 1952322711 "HALOPERIDOL"                    11
1952310666 "Haloperidol"                     42 1942322110 "HALOPERIDOL"                    53
1740284074 "Haloperidol Lactate"             54 1316013006 "IPRATROPIUM BROMIDE"            15
1326224932 "Hydroxyprogesterone Caproat/Pf"  11 1386731396 "IPRATROPIUM BROMIDE"            20
1053419028 "Indomethacin"                    11 1831190982 "IPRATROPIUM BROMIDE"            32
1306948609 "Ipratropium Bromide"             19 1760486443 "LEUPROLIDE ACETATE"             12
1477538734 "Isosorbide Dinitrate"            11 1467453613 "LORAZEPAM"                     106
1518941293 "Leuprolide Acetate"              26 1467443838 "LORAZEPAM"                      88
1700958659 "Lidocaine Hcl"                   18 1922186428 "LORAZEPAM"                      13
1952310666 "Lorazepam"                      265 1255363719 "LORAZEPAM"                      11
1316029341 "Mafenide Acetate"                11 1629037775 "MORPHINE SULFATE"               12
1265587869 "Meperidine Hcl"                  21 1770514242 "MORPHINE SULFATE"               19
1275737389 "Meperidine Hcl/Pf"               76 1508839093 "MORPHINE SULFATE"               24
1003889502 "Methocarbamol"                   14 1346252525 "MORPHINE SULFATE"               18
1952310666 "Methylphenidate Hcl"             30 1710234315 "MUPIROCIN"                      57
1437266202 "Midodrine Hcl"                   16 1972603793 "MUPIROCIN"                      17
1003889502 "Morphine Sulfate"                28 1447339452 "MYCOPHENOLATE MOFETIL"          24
1295757904 "Morphine Sulfate/Pf"             22 1770677726 "NYSTATIN"                       12
1326330127 "Mupirocin"                      114 1811907108 "NYSTATIN"                       13
1093808966 "Mupirocin Calcium"               13 1174785950 "OSELTAMIVIR PHOSPHATE"          44
1144305301 "Mycophenolate Mofetil"           50 1457353500 "OSELTAMIVIR PHOSPHATE"          13
1700958659 "Nitrofurantoin"                  19 1124219092 "ROSUVASTATIN CALCIUM"           50
1477538734 "Nitrofurantoin Macrocrystal"     16 1043220957 "ROSUVASTATIN CALCIUM"           40
1225023872 "Nystatin"                        18 1720011380 "ROSUVASTATIN CALCIUM"           48
1164404232 "Ofloxacin"                       11 1467426122 "ROSUVASTATIN CALCIUM"           23
1700958659 "Oseltamivir Phosphate"           17 1659324820 "ROSUVASTATIN CALCIUM"           88
1770555922 "Penicillamine"                   12 1447474945 "ROSUVASTATIN CALCIUM"           27
1417924309 "Proparacaine Hcl"                24 1225030547 "ROSUVASTATIN CALCIUM"           36
1891993317 "Rosuvastatin Calcium"            12 1134231822 "ROSUVASTATIN CALCIUM"          125
1235102187 "Scopolamine"                     19 1205863701 "SPIRONOLACTONE"                 57
1477581320 "Sodium Chloride"                 50 1659322899 "SPIRONOLACTONE"                 82
1235102187 "Sodium Chloride 0.45 %"          12 1255443891 "SPIRONOLACTONE"                 27
1881791820 "Sodium Chloride 3 %"             45 1962404780 "SPIRONOLACTONE"                 29
1396812202 "Sodium Chloride For Inhalation"  18 1699042457 "SPIRONOLACTONE"                 36
1619134244 "Sodium Chloride Irrig Solution"  12 1467550095 "SPIRONOLACTONE"                 51
1467420893 "Sodium Polystyrene Sulfonate"    12 1619921194 "SPIRONOLACTONE"                 14
1225023872 "Spironolactone"                  57 1366684714 "SPIRONOLACTONE"                 11
1013964634 "Temazepam"                       14 1659469856 "VALSARTAN"                      11
1952310666 "Thiothixene"                     20 1780797837 "VALSARTAN/HYDROCHLOROTHIAZIDE"  33
1952310666 "Trifluoperazine Hcl"             31 1992771000 "VALSARTAN/HYDROCHLOROTHIAZIDE"  39
1437266202 "Valsartan"                       35 1780810572 "VALSARTAN/HYDROCHLOROTHIAZIDE"  15
1952395717 "Valsartan/Hydrochlorothiazide"   34          . ""                                .
end