Relationship with existing table

[goslincm]

I just cannot get beyond this spot. I have an existing table which looks like:
LocalUnitTable
CountyCd
LocalUnitType
LocalUnitCd
OfficeID(PK)

I need to start now combine some existing information that is stored in 2 other tables into the mix. The two other tables with existing information look like:

PopulationTable
CountyCd*
LocalUnitType*
LocalUnitCd*
PopulationYear*
Population

TaxValueTable
CountyCd*
LocalUnitType*
LocalUnitCd*
TaxYear*
TaxValue

I do not know how to work with these existing tables to come up with a new one to combine it all.

 

[PHV]

Have a look here:

http://www.devshed.com/c/a/MySQL/Understanding-SQL-Joins

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[goslincm]

As much as that was a great article, I'm still not able to join my tables correctly after reading it.

 

[PHV]

Something like this ?
SELECT L.CountyCd, L.LocalUnitType, L.LocalUnitCd, L.OfficeID, P.PopulationYear, P.Population, T.TaxYear, T.TaxValue
FROM (LocalUnitTable AS L
INNER JOIN PopulationTable AS P ON L.CountyCd=L.CountyCd AND L.LocalUnitType=P.LocalUnitType AND L.LocalUnitCd=P.LocalUnitCd)
INNER JOIN TaxValueTable AS T ON P.CountyCd=T.CountyCd AND P.LocalUnitType=T.LocalUnitType AND P.LocalUnitCd=T.LocalUnitCd AND P.PopulationYear=T.TaxYear


Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886