Question

I need to copy a column from one table to another. The problem is matching the values with the right rows.

INSERT INTO DestinationTable (money_owed)
SELECT "credit"
FROM SourceTable

How do I search through the destination table and compare another field to see if it’s the same one in the source table?

Answer 1

You need to join the two tables on the matching condition.

Something like this

UPDATE
   DestinationTable 
SET 
   DestinationTable.money_owed = SourceTable.Credit
FROM
   DestinationTable 
INNER JOIN SourceTable
ON DestinationTable.Field2 = SourceTable.Field2