SQL command error for multiple value condition in other table column; : We want to add a new column which values are depending by lots of condiction 

For example, there are lots of bin numbers refer to different country like this bin number table

Start_Bin     End_Bin     Country_Code

4976999             4971000           US

4986999             4990000           UK

4920000             4929999           US


And we want to create a new column of country code on a table which's condiction is base on this table

This is our sql code, which is not allowed by sql server :(

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    ALTER Table temp.we_are_foreigners__table ADD COLUMNS CASE

     

        WHEN (CAST(temp.we_are_foreigners__table.accountno AS int) >= CAST(temp.visa_country_classify_table.start_binnumber AS int) AND CAST(temp.we_are_foreigners__table.accountno AS int) <= CAST(temp.visa_country_classify_table.end_binnumber AS int) ) THEN temp.mastercard_country_classify_table.country_code

        WHEN (CAST(temp.we_are_foreigners__table.accountno AS int) >= CAST(temp.mastercard_country_classify_table.start_binnumber AS int) AND CAST(temp.we_are_foreigners__table.accountno AS int) <= CAST(temp.mastercard_country_classify_table.end_binnumber AS int) ) THEN temp.mastercard_country_classify_table.country_code

        END As Country_String

       

    from temp.visa_country_classify_table, temp.mastercard_country_classify_table, temp.we_are_foreigners__table;

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What's the proper SQL command of doing this, what's the problem? 