Need to insert 4 columns into a table, but only if they don't already exist

[raynman1972]

I have two tables that have 5 columns in common, but there are rows missing from one that are present in the other. Can I use "WHERE NOT EXISTS", or something similair, that can select these rows from table A that are missing from table b so that I can insert them? As some background, one table is based off of forecasted data and the other is based off of actuals and the delta is that there are some intervals where, despite there being a forecast, there are no actuals.

SELECT 
 DAT_WWCP_STF_DATA.SITE
,DAT_WWCP_STF_DATA.FCST_GROUP
,DAT_WWCP_STF_DATA.INTERVAL AS ARRIVAL_INTERVAL
,DAT_WWCP_STF_DATA.DATE AS ARRIVAL_DATE
,DAT_WWCP_STF_DATA.FORECAST

FROM DAT_WWCP_STF_DATA

WHERE NOT EXISTS
(
SELECT
 EMAILS_RESOLVED_SUMMARY.SITE
,EMAILS_RESOLVED_SUMMARY.FCST_GROUP
,EMAILS_RESOLVED_SUMMARY.ARRIVAL_INTERVAL
,EMAILS_RESOLVED_SUMMARY.ARRIVAL_DATE
,EMAILS_RESOLVED_SUMMARY.FORECAST

FROM EMAILS_RESOLVED_SUMMARY
);

[TheShabz]

is there a common unique field between the two tables?

[raynman1972]

Unfortunately, no.

[TheShabz]

Ok. Are you looking for exact duplicates? If so, you can just append to the table, then do
SELECT (every field without using *)
INTO (New table name)
FROM (The table)
GROUP BY (every field)

Which will remove every exact duplicate record, leaving you with one.

You can then delete the old table (make a backup first to make sure it all works correctly) and rename the new one. It's pretty kludgy but if you have no identifying field, you don't have many options.

[raynman1972]

Yeah, I think that would do it. I agree that this would not be a very elegant solution and I have not found anything else for alternative. Thanks for your time and reply