SQL & PL/SQL

From the below table example, I'm trying to identify only the records where VAL_IN changed. So I need to see only 4 records in the below example.
I've been reading about LEAD / LAG and think this is probably the function I need to use, but have not had luck with returning results. Can someone please help push me in the right direction.

Good afternoon people!

I have a procedure in Oracle with various functions of calculations, type simulator. So, I want to assemble a type with output parameters reading this data and bring the results of these functions in real time, because I want to display them as output lines on a front (web screen). I already created the types objects and table. However, I am having difficulty assembling, because I do not know well Type. Can someone help me? Thanks

Decision Tree Algorithm in pl/sql
Author JP Vijaykumar
Date Sept 14th 2019

SELECT tablespace_name ,round(TOTAL_SIZE,2) ,round(TOTAL_SIZE-FREE_SIZE,2) ,
round(FREE_SIZE,2)
FROM (SELECT tablespace_name,(SELECT SUM(BYTES)/1024/1024/1024 FROM DBA_DATA_FILES b WHERE b.TABLESPACE_NAME=a.TABLESPACE_NAME)TOTAL_SIZE,
SUM(bytes)/1024/1024/1024
FREE_SIZE
FROM DBA_FREE_SPACE a GROUP BY tablespace_name) order by 1;

Tablespace Capacity Planning Report
Author JP Vijaykumar
Written Sep 14 2017
Modified Mar 08 2019
***************************************************************************************************************
This script is provided for enducational purpose only.
The readers are advised to make necessary changes to the script as may be required for their use in their repective environments.
Pls test this script thoroughly in a lower environment, before using in any production db.

********************************************************************************
APRIORI ALGORITHM
********************************************************************************
Modified March 08 2019

********************************************************************************
--LINEAR REGRESSION ALGORITHM IN PL/SQL
--------------------------------------------------------------------------------
Modified Mar 8th 2019
Using Linear Regression algorithm, find the weight of a studen, whose is 71 inches tall.
Given the height and weight of 8 students.

--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.

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;

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.