Keeping only unique records

jomama

I have a table with about 500 records. I have another table that has another 5,000. I want the 5,000 records from the second table to populate the table that has 500 records.

1st Note: Here's the catch. If the same record exists in both tables I want to keep the one that is in the original table(the one with 500 records). Basically never delete any records in the original table.

2nd Note: Also, there is no Primary Key. So, to identify if the records are the same, I would need to compare 3 fields(firstname, lastname and companyname):

Basically, delete record from 2nd table if there is a matching record in the 1st table. Then, I could easily combine them.

Can this be done with a SQL statement? If not, can someone suggest how I can go about this programmatically?

Thanks SO much in advance.
Josu

Cloud

I have actually tried doing that before. Little differnt though. I wanted to populate a 'privledges' table that already had a few users in it with users that were in my 'users' table.

I did something wrong and ended up with about 1,000 duplicates. So obviously my attempt failed. I think it was because I kept running it over and over again and didn't have anything to stop it from duplicating the records though.

Basicaly though, its a matter of comparing the records from the two tables.

Select a record from the 5,000 record table. And create a while() loop. Probably where you query the array or object (up to you how you pull the result.

So:
while($result = mysq_fetch_array($data)) {

(insert compare script)

}

The compare script would basicaly have the values from the 5,000 table and would be matching it again every single record from the original table.
If it finds a match it stops comparing and moves on to the next record.
And after its gone through all the records in the origianl table and still remains unmatched insert it.