CODEWITHSUNDEEP
databasevb.net
user1570048
user1570048

Reputation: 880

vb.net comparing two databases then insert or delete

in vb.net how would you loop through database1 to check that all records in database2 exist in Database1 and the other way areound if a record exist in database1 and doesnt exist in database2 then delete it from database1. so database2 is my reference

how can i do this using queries, also does it have to include nested looping?

note that the records are not in the same order

Thanks

Upvotes: 1

Views: 873

Answers (1)

RBarryYoung
RBarryYoung

Reputation: 56755

This query will return all of the rows in the attached table that are not in the local version of the table

SELECT * FROM attachedTable 
WHERE col1 NOT IN( SELECT lt.col1 FROM localTable as lt)

And this will do the converse, returning all rows in the local table that are not matched in the remote table.

SELECT * FROM localTable 
WHERE col1 NOT IN( SELECT rt.col1 FROM attachedTable As rt)

Upvotes: 1

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