Question

I have two tables

articlesdownloadtrack with columns – id, articleid, createdtime, modifiedtime

articles with columns – id, articlename, articleURL, createdtime, modifiedtime

Some of the entries in articlesdownloadtrack i.e. articlesdownloadtrack.articleid are not available in articles(missed during the process of migration). I want to remove such records.

I am using the query

delete from articlesdownloadtrack where articleid not in(select id from articles); 

But I have to add a constraint to delete only those records whose articleid is not null, because in articlesdownloadtrack, there are some records whose articleid is NULL, which should not be deleted when this query is executed.

Answer 1

As mentioned @njk , try this :

 delete 
     from articlesdownloadtrack 
 where 
    (
     articleid IS NOT NULL AND articleid not in(select id from articles)
    )