Update table based on values from a different table

[utahjzz98]

I have a .csv file with several hundred million records that I have imported into a SQL Server table. In an attempt to normalize the data, I have created several sub tables that contain ID for several respective values contained in the main table. I am looking to update the values in the main table with their respective ID’s from the sub tables, but I am unsure of how to accomplish this.

As a small example of what I am trying to accomplish:
Table 1 contains FName, LName, Address, City, State, Zip, etc
Table 2 contains CityID, StateID, etc
I want to look for any value for City in Table 1 that equals 'Chicago', reference table 2 with the appropriate CityID for Chicago, and update Table1 with the matching CityID

 

[utahjzz98]

I also want to add that I am aware of using Update [table name] Set [column name]=’[integer]’ where City = ‘chicago’, but due to the large number of rows, I don't want to have to manually update each ID separately.

 

[imex]

Try something like this:

update t1
set CityID = t2.CityID
from Table1 as t1
join Table2 as t2
    on t2.City = t1.City

Hope this helps.

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