Re: Why the two sql result is different?

[Harald Bacik]

Hey

Not sure, what you try to do.
The first select only tells you, that the two values are equal 1 = true
The second select does not make sense to me.

You try to get all data from both tables, where js = tx are the same, what is not happen. So it would be either JS or TX. So, the result is empty

You should check out joins

https://dev.mysql.com/doc/refman/8.4/en/join.html