Question

Well i am trying a statement like this..

UPDATE pubs SET pubs.id=parentid.id WHERE parentid.title=pubs.title

well id is the primary key of parentid ..

the error thrown up is

Error:Unknown column 'parentid.title' in 'where clause'

Help appreciated

Answer 1

I’m not sure what you’re looking for. The key is that you need to specify the parent-child join in your SQL.

If your parents are already setup in a self-referential join, use the following:

UPDATE p
SET p.id=parentid.id
FROM pubs p
JOIN pubs parent
ON parent.id = p.parentid
WHERE parent.title=p.title

If you’re looking to define parent-child relationships based on the titles, use this:

UPDATE p
SET p.id=parentid.id
FROM pubs p
JOIN pubs parent
ON parent.title=p.title