Comments on: Column with Duplicate Values

By: The Most-Watched IT Questions: January 18, 2012 - ITKE Community Blog

The Most-Watched IT Questions: January 18, 2012 - ITKE Community Blog — Thu, 19 Jan 2012 20:33:28 +0000

[...] 8. Carlosdl, TomLiotta, and Lorit give their ideas about columns with duplicate values. [...]

By: lorit

lorit — Wed, 11 Jan 2012 12:45:27 +0000

Answer Wiki:
This doesn’t fit too good – but the numbers beginning with 159 are from the FMV column. There are two records with the same amount 5880 – it only returns one record because the value is the same. How can I get around this without having it generate all duplicates?

Dist Status Name Id
Code Date Number Parcel Name Year House Nr Street Address line 2 City St Zip # MH # Boats FMV
—- ———- ——- ——- —————————— —- ———- —————– ——————– ————— — —– —- ——- ———-
1159 2011/08/23 378207 0007127 BARRIER ISLAND INC 2011 328 FRONT ST BEAUFORT NC 28516 0 7 50
0 7 159
0 7 2100
0 7 5880
0 7 9180
0 7 9286
0 7 11360
0 7 19344
0 7 54164
———-
111523
==========
111523

By: tomliotta

tomliotta — Mon, 09 Jan 2012 23:48:37 +0000

…when the column C. PC_FMV has two records with the same value…

As Carlosdl says, DISTINCT is going to eliminate duplicate rows. That’s one of its fundamental purposes.

If you need those two rows both to show up, you will probably need to include something else from “QS36F”/”T16.PCTG” C that distinguishes the two rows. One complication is that any additional column from that file might cause every row to be unique which could mess up the rest of DISTINCT.

You might try creating something like a DISTINCT VIEW over the other three files without including “QS36F”/”T16.PCTG” C. And then use that VIEW to join to “QS36F”/”T16.PCTG” C. That would effectively be a ‘table expression’ which is a possible alternative. The VIEW (or ‘table expression’) would be DISTINCT by itself; but when joined to “QS36F”/”T16.PCTG” C, it could give duplicates in the final result set. The DISTINCT should apply only to the three files in the VIEW.

Without knowing the possible data, it’s hard to say whether that would work or not.

Tom

By: carlosdl

carlosdl — Mon, 09 Jan 2012 21:58:46 +0000

If the duplicate data in C.PC_FMV causes the whole returned record to be duplicate, then the DISTINCT keyword will remove it from the result. But I’m not sure if that is what you meant. If not, I would recommend posting some example data with its expected results.