How to update rows in one table depending on another table

[aas1611]

Hi!

Maybe my subject is a little confusing. So I hope the following can make it clearer:

I have two tables, T1 and T2. These two have (almost) identical fields. In fact, we can assume that T2 is a copy of T1. The unique field for both is ID. Each table has 11K rows. The difference is, T1 is a table in mysql, and T2 is a table in Access. I made a link to T1 from Access.

The problem:
if someone makes changes on T1 (from internet) for some particular row(s), these changes have to be updated also in T2 (from Access).

How can I make a good query in Access for this purpose?

Thanks for any hint!

Andre

 

[Golom]

The general approach is

UPDATE T1 INNER JOIN T2
       ON T1.ID = T2.ID

SET    T1.Fld1 = T2.Fld1

WHERE T1.Fld1 <> T2.Fld1 
   OR T2.Fld1 IS NULL 
   OR T1.Fld1 IS NULL

on an individual field basis. You need the IS NULL bits because comparison operators (like <>) don't work correctly on NULLs.