Change post content

Hi.

I’ve imported an old wordpress blog to a new one.
In the old one, most posts have the images with the whole path:

<img src=”https://www.oldsite.com/images/file.jpg”&gt;

so now, with the new domain, they do not work.
I have like a thousand posts so I was wondering if there is a way (maybe with phpMyAdmin) to look for a content (www.oldsite.com) and replace it with https://www.newsite.com.
I’m not familiar with phpMyAdmin and nor a SQL expert so any help would be appreciated.

Thank you all.