I may have missed a trick here but I can't seem to find a solution.
I have a table of ~1.6 million postcodes, also containing co-ordinates, and a separate file detailing ~6000 a population with postcodes attached. I am trying to attach the co-ordinates from the postcode file to the population file. There is, but not always, two or more individuals associated to one postcode. The theory, in my head, is simple. Join the postcode table to the population table on the postcode attribute. To start with this idea in ArcGIS 10.1 seemed simple, using a basic join, but what seems to be happening is that a 1:1 relationship is being enforced. After researching further I found the Make Query Table tool which claimed to solve this M:1 problem. Though that doesn't seem to be working. I am currently in a two-step process to see if I can solve this. First is looking through some, don't particularly want to look through all files in either table, to see if there is a formatting error that would explain this error. The second is looking into using MySQL to see if that can be used to join the tables. Or at least create a query of the two tables that will produce the desired output table.
First off if you have any advice on making this work in ArcGIS that'd be brilliant, I'm sure it can do it, just not sure how to make it work. Alternatively if you know of another method that would easily join these tables, be that QGIS, MySQL or something else, then please do say.
Hope you can help, and if there's anything I've missed out that would help you understand my problem, let me know.