Question

I would appreciate some help on creating the proper SQL to retrieve only one value for matching records in my 3rd table “table C” as shown below. Table A lists customers ID, name and state. Table B lists foreign key customers ID and member card number. Table C lists sales for member card number.

select  A.cifno, A.cfna1, A.cfstate, B.hbmast.cifno, B.hbmast.hbcid,  C.cast(ewmast.ewcid as dec(12,0)) as "eWire ID"
from library.cfmast cfmast join library.hbmast hbmast
on cfmast.cfcif# = hbmast.cifno left join library.ewmast ewmast
on hbmast.hbcid = cast(ewmast.ewcid as dec (12,0))

Sample data:

table A
**A.cifno, A.cfna1, A.cfstate**
J00022, John, OH
B00019, Ben, TX


table B
**B.hbmast.cifno, B.hbmast.hbcid**
J00022, 555500001234
B00019, 555500007878


table C
**ewmast.ewcid**
555500001234
555500001234
555500001234
555500007878

Desired output is:

J00022, John, OH, J00022, 555500001234, 555500001234
B00019, Ben, TX, B00019, 555500007878, 555500007878

— NOT —

J00022, John, OH, J00022, 555500001234, 555500001234
J00022, John, OH, J00022, 555500001234, 555500001234
J00022, John, OH, J00022, 555500001234, 555500001234
B00019, Ben, TX, B00019, 555500007878, 555500007878

Answer 1

You should use the keyword distinct in your select.

I.e., something like:

select distinct ....