SQLite - UPSERT *not* INSERT or REPLACE

Question

http://en.wikipedia.org/wiki/Upsert

Insert Update stored proc on SQL Server

Is there some clever way to do this in SQLite that I have not thought of?

Answer 1

The best approach I know is to do an update, followed by an insert. The "overhead of a select" is necessary, but it is not a terrible burden since you are searching on the primary key, which is fast.

You should be able to modify the below statements with your table & field names to do what you want.

--first, update any matches
UPDATE DESTINATION_TABLE DT
SET
  MY_FIELD1 = (
              SELECT MY_FIELD1
              FROM SOURCE_TABLE ST
              WHERE ST.PRIMARY_KEY = DT.PRIMARY_KEY
              )
 ,MY_FIELD2 = (
              SELECT MY_FIELD2
              FROM SOURCE_TABLE ST
              WHERE ST.PRIMARY_KEY = DT.PRIMARY_KEY
              )
WHERE EXISTS(
            SELECT ST2.PRIMARY_KEY
            FROM
              SOURCE_TABLE ST2
             ,DESTINATION_TABLE DT2
            WHERE ST2.PRIMARY_KEY = DT2.PRIMARY_KEY
            );

--second, insert any non-matches
INSERT INTO DESTINATION_TABLE(
  MY_FIELD1
 ,MY_FIELD2
)
SELECT
  ST.MY_FIELD1
 ,NULL AS MY_FIELD2  --insert NULL into this field
FROM
  SOURCE_TABLE ST
WHERE NOT EXISTS(
                SELECT DT2.PRIMARY_KEY
                FROM DESTINATION_TABLE DT2
                WHERE DT2.PRIMARY_KEY = ST.PRIMARY_KEY
                );