SQL & PL/SQL

SQL and PL/SQL Articles

NAIVE BAYES ALGORITHM WITH SQL & PL/SQL

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--NAIVE BAYES ALGORITHM WITH SQL & PL/SQL
---------------------------------------------------------------------------------
--Written JP Vijaykumar
--Date Jan 4th 2019

--This script is provided for educational purpose only.
--The readers are advised to make necessary changes as may be required for their use.

--I love data mining algorithms for their complexity and number crunching toughest logic.
--Academically, I want to generate Naive Bayes algorythm in pl/sql to predict the outcome.

Sending Email from PLSQL from Gmail

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How to send Email in Oracle using Gmail.
Email sending by using Oracle through Gmail:

BEGIN EMAIL_GMAIL.SEND ('shabbier.sa@gmail.com','shabbier.sa@gmail.com','Your email subject','Emaisaaasdasal Message body'); END;

Tuning with equivalent SQLs - a little challenge

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I am fascinated by what I call "equal SQL": statements that are equivalent, in that they deliver the same result but may have hugely different performance characteristics. Here's a little case study.

Is row-by-row processing really slow-by-slow? Emphatically: YES

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Developers who come to Oracle with a background in procedural languages sometimes do not understand how efficient SQL's set oriented processing can be. This little demonstration should convince them: never use PL/SQL when SQL will do.

How to change column order when using SELECT *

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We all know that using SELECT * is bad programming. One reason is that you cannot control the order in which columns are returned. Well, you can in release 12c.

Roles , PL/SQL, and ORA-00942: table or view does not exist

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Many developers find that their code fails with ORA-942, but when they test the failing statement from the SQL> prompt, it works. Why, and what can you do to fix it?

Natalka Roshak's picture

Recursive WITH, part III: IS_LEAF

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The CONNECT BY syntax provides a useful pseudocolumn, CONNECT_BY_ISLEAF, which identifies leaf nodes in the data: it’s 1 when a row has no further children, 0 otherwise. In this post, I’ll look at emulating this pseudocolumn using recursive WITH.

Natalka Roshak's picture

Recursive WITH, part II: Hierarchical queries

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In my last post, I looked at using recursive WITH to implement simple recursive algorithms in SQL. One very common use of recursion is to traverse hierarchical data. I recently wrote a series of posts on hierarchical data, using Oracle’s CONNECT BY syntax and a fun example. In this post, I’ll be revisiting the same data using recursive WITH.

Natalka Roshak's picture

Recursion with recursive WITH

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I recently had the opportunity to talk with Tom Kyte (!), and in the course of our conversation, he really made me face up to the fact that the SQL syntax I use every day is frozen in time: I’m not making much use of the analytic functions and other syntax that Oracle has introduced since 8i.

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