Good morning. My Doubt is: Which is better in terms of readability and performance, use subqueries whenever possible or use the "join" format? What is more important, readability or performance? I would understand that many would say that if the difference in performance is not going to be very large that the readability prevails.
Select * from t1
inner join t2 on t1.k1=t2.k2
O
Select * from t1,t2
where t1.k1=t2.k2
Is there an alternative way to use left or right join to get the null values, as in oracle when using the (+)?
select n1,n2
from t1 left join t2 on t1.n1=t2.n2
n1 n2
-- --
2 2
3 3
1 NULL
4 NULL
A year or so ago I remember a complete guide to mysql or sql to dry with all the syntax of each aspect of mysql, detailed and explained how each keyword and operation worked and now I am not able to find such documentation. Only a very summary documentation of the sentence syntax.
