All posts under SQL

Diving into Oracle Analytical Functions part 2/2


Hello all and welcome back for the second part of this post ! As promised, on the previous post , I will cover RANK function, DENSE RANK and ROW_NUMBER analytical functions. RANK The rank function allows us to rank a value in a group of values.The Oracle rank function comes in[…]

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Diving into Oracle Analytical Functions part 1/2


Hi all ! A couple of weeks ago I felt the need to research a little further on Oracle Analytical Functions. They are so powerfull, yet, only a couple of PLSQL programmer friends were into them. Before beginning this post, let me just make a brief intro. There are 6 types[…]

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Oracle subquery caching


On Oracle there’s a kind of cache that works with scalar subqueries (look below for a simple example of a scalar subquery) which prevents the database engine to repeat unnecessary work to get the same result again and again. But while this seems to be less than useful with pure Oracle[…]

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SQL performance tip of the day 11g


Hi all ! After all the big changes we’re now fully back to our posts ! Today’s post will focus on an SQL performance tip. A couple of days ago I just came across with a performance problem regarding a join between a table and a collection. Apparently the Oracle[…]

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Working with hierarchies in Oracle


Hi all! One of the most used database concept is  hierarchies. Why? Basically, any relation that can be categorized as a “Father” – “Son” relationship can take advantage of this concept. Lets us imagine you want to represent the relationship between an employer and an employee. You could probably create two[…]

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