How to return NULL in LEFT JOIN? [closed]

Question

How to return NULL in LEFT JOIN? [closed]

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#1 by (1 votes)

1

I have 2 tables that I need to manipulate:

intervencaoprioridade: idintervencaoprioridade, idcelula ...

cell: idcelula, name ...

SELECT ip.idintervencaoprioridade, zc.nome nome_celula 
FROM intervencaoprioridade ip 
LEFT JOIN celula zc ON ip.idcelula = zc.idcelula 
WHERE ip.idintervencaoprioridade = 22

The field ip.idcelula can be NULL , but when I do this query it returns the first record of the celula table. I've seen other examples in SO , but I did not see anything that would help me.

sql

asked by anonymous 14.10.2015 / 19:07

1 answer

Am I abusing Strategy Pattern in Java? Display report of MySQL tables

score 1 · Accepted Answer

This can happen to more users as in my case, I leave my answer and solution if it is useful to others.

When I tested for a id = 22 it did not have the field idcelula to null so it returns another value that by coincidence was the first. Taking the test more carefully I noticed that, and changed the test record to one that had idcelula to null .