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Tag: self-join

How self join works [closed]

Closed. This question needs debugging details. It is not currently accepting answers. Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question. Closed 2 years ago. Improve this question I hav…

Python Pandas non equal join

Have table OUT Need: so i need make non equal join equivalent SQL query : or as SQL query: The problem in PANDAS is that NON EQUAL SELF JOIN cannot be done with MERGE. And I can’t find another way….. Answer We can solve this in pandas in a smarter way by using groupby with agg and joining the stri…

MySQL self join to find only the next revision

Actually I’m working with WordPress. I want to create a self-join or something similar to find a revision of a post, and the following revision of the same post. https://www.db-fiddle.com/f/eHnwYABYrVVQAhn8xLJ77q/1 The previous query doesn’t work since it takes, for every record of a, all the revi…

MySQL category with parent_id – SELF Join

My SQL table called categories has the following structure: I would like to know if it’s possible to JOIN the same table and present the parent_id name. I can do this by PHP code, but I would like, because of performance issues, to retrieve as SQL Query. See example at SQLFiddle I’ve managed to JO…