Matching and Comparing data from sheet1 to sheet2

[appreciateyourhelp]

Hello there,
sorry if this has been asked before - I don't know the lingo yet ; )
I would like to match 3 to 4 columns of data in a row in sheet 1 to the same data and amount of columns in Sheet 2 a
ie matching between Project ID & Activity Id & Activity Name
and find differences in one or two the columns ie: % completed and Activity Status

What I trying to find is when data has been updated (not when it remains the same) can I highlight the changed in the data in current week ?
I was thinking to make it easy to update each week I could insert new data into the same columns in Sheet 1 (last weeks data) and Sheet 2 (this weeks data) each week and keep the formula in sheet 3 ?

I have found when I concatenate I sometimes get a problem when a user has added extra spaces after a word or number or when the dash changes from a short dash to a long dash, problems like that are stopping me from matching in concatenation correctly and I have thousands of rows to check so want to make it easy and successful
I really appreciate your reading this and helping if you can - thank you Helen ; )

for example :

Sheet 1 (last weeks data)
Project ID (column 1 title)

[TABLE="width: 678"]
<tbody>[TR]
[TD]Project ID[/TD]
[TD]Activity ID[/TD]
[TD]Activity Name[/TD]
[TD]Start[/TD]
[TD]Finish[/TD]
[TD]% Complete[/TD]
[TD]Activity Status[/TD]
[/TR]
[TR]
[TD]ABC-234-65[/TD]
[TD]MOB-123[/TD]
[TD]activity name 1[/TD]
[TD]12-Jan-17 A[/TD]
[TD]12-Jan-17 A[/TD]
[TD="align: right"]1[/TD]
[TD]COMPLETED[/TD]
[/TR]
[TR]
[TD]ABC-234-65[/TD]
[TD]DRP-123[/TD]
[TD]activity name 2 [/TD]
[TD="align: right"]15/05/2017[/TD]
[TD="align: right"]19/05/2017[/TD]
[TD="align: right"]0[/TD]
[TD]NOT_STARTED[/TD]
[/TR]
[TR]
[TD]ABC-234-66[/TD]
[TD]DRP-2032[/TD]
[TD]activity name 3[/TD]
[TD]04-Apr-17 A[/TD]
[TD="align: right"]30/06/2017[/TD]
[TD="align: right"]0.3001[/TD]
[TD]IN_PROGRESS[/TD]
[/TR]
[TR]
[TD]ABC-234-66[/TD]
[TD]DRP-2033[/TD]
[TD]activity name 4[/TD]
[TD]04-Apr-17 A[/TD]
[TD="align: right"]30/06/2017[/TD]
[TD="align: right"]0.3001[/TD]
[TD]IN_PROGRESS[/TD]
[/TR]
</tbody><colgroup><col><col><col><col span="2"><col><col></colgroup>[/TABLE]



Sheet 2 (this weeks data)

[TABLE="width: 678"]
<tbody>[TR]
[TD]Project ID[/TD]
[TD]Activity ID[/TD]
[TD]Activity Name[/TD]
[TD]Start[/TD]
[TD]Finish[/TD]
[TD]% Complete[/TD]
[TD]Activity Status[/TD]
[/TR]
[TR]
[TD]ABC-234-65[/TD]
[TD]MOB- 123[/TD]
[TD]activity name 1 [/TD]
[TD]12-Jan-17 A[/TD]
[TD]12-Jan-17 A[/TD]
[TD="align: right"]1[/TD]
[TD]COMPLETED[/TD]
[/TR]
[TR]
[TD]ABC-234-65[/TD]
[TD]DRP-123[/TD]
[TD]activity name 2 [/TD]
[TD="align: right"]42870[/TD]
[TD="align: right"]42874[/TD]
[TD="align: right"]0[/TD]
[TD]NOT_STARTED[/TD]
[/TR]
[TR]
[TD]ABC-234-66[/TD]
[TD]DRP-2032[/TD]
[TD]activity name 3[/TD]
[TD]04-Apr-17 A[/TD]
[TD="align: right"]42916[/TD]
[TD="align: right"]0.3001[/TD]
[TD]IN_PROGRESS[/TD]
[/TR]
[TR]
[TD]ABC-234-66[/TD]
[TD]DRP-2033[/TD]
[TD]activity name 4[/TD]
[TD]04-Apr-17 A[/TD]
[TD="align: right"]42916[/TD]
[TD="align: right"]0.3001[/TD]
[TD]IN_PROGRESS[/TD]
[/TR]
</tbody><colgroup><col><col><col><col span="2"><col><col></colgroup>[/TABLE]

 

[appreciateyourhelp]

sorry meant to make these changes
Imagine I have changed in Sheet 2
under % complete from 30 % to 45% and Activity Status changes from In-progress to completed