Do It With SQL - Journey to the Center of Database Worlds

DoItWithSQL
JourneytotheCenterof
DatabaseWorld
PHPID COMMUNITY ONLINE MEETUP #20 – 08/05/2020
BERSAMA: NUR HIDAYAT - DATABASE SPECIALIST

KebanyakanProgrammer,lebihsuka....
MENINGKATKAN SKILL
BAHASA PEMROGRAMAN
TERBARU,
MEMBUAT USER INTERFACE
YANG ATRAKTIF DAN USER-
FRIENDLY,
MEMBUAT APLIKASI YANG
BISA BERJALAN DI
DATABASE APAPUN
08/05/2020PHPIDONLINEMEETUP–CODEFACTORY

Akibatnya.....
o Kurang piawai meracik perintah SQL
o Tidak memanfaatkan fitur canggih yang ada di Database
o Membawa gaya pemrograman prosedural saat memproses data

JourneytotheCenterofDatabaseWorld
oDon’t treat databases as a black box
olearn what it can do for us

RuleofThumbs
Use single SQL
statement
whenever
possible
1
Use Stored
Procedure
(PL/SQL, T-SQL,
PL/pgSQL)
2
Use Java (or other
programming
language, such as
PHP, Go, etc.)
3
Rethink why you
want to do it
(refine your
approach)
4

SQLAnatomy
o Statement/Query
o Clause
o Predicate
o Expression

SELECTStatementBasics
SELECT b,d,e,h
FROM some_table ;
SELECT *
FROM some_table
WHERE x IN (3,5,6,8) ;
SELECT b,d,e,h
FROM some_table
WHERE x IN (3,5,6,8) ;

SQLJOINBasics
oSTANDARDJOIN
◦ INNER JOIN (JOIN)
◦ LEFT OUTER JOIN (LEFT JOIN)
◦ RIGHT OUTER JOIN (RIGHTJOIN)
◦ FULL OUTER JOIN (FULLJOIN)
oADVANCEDJOIN
◦ LEFT EXCLUDING JOIN
◦ LEFTJOINEXCLUDINGINNER JOIN
◦ RIGHT EXCLUDING JOIN
◦ RIGHTJOINEXCLUDINGINNER JOIN
◦ FULL EXCLUDING JOIN
◦ FULLJOIN EXCLUDING INNER JOIN

Representasi
VisualSQLJoin
o Diagram Venn
o Red Color is the result

JOINvsUNION

ChangeYour
Mindset!
o Tampilkan angka 1 sampai dengan 100,
dengan persyaratan sebagai berikut,
◦ setiap kelipatan3 ubah angkanya menjadi
kata ”PHP",
◦ setiap kelipatan 5 ubah angkanya menjadi
kata ”Indonesia", dan
◦ setiap kelipatan 15 ubah angkanya menjadi
kata ”PHP Indonesia".

Discussion D O I T W I T H S Q L

CaseStudies LET DATABASE SOLVE
OUR PROBLEMS

CaseStudies
oComputed column in query
oGenerated column in table
oJoin and Union
oAggregation
oSubqueries
oCommon Table Expression
oPivot/Crosstab Query
oCalculating Running Totals
oAnalytical Query
oHierarchical Query

ComputedColumn(Query)
o Most common problem
◦ I want field amount amount
automatically filled with value =
quantity * unit_price
o Solution
◦ Don’t create field amount
◦ Calculate value using query or view
o Sample data available here

ComputedColumn(Table)
o Use Generated Column
◦ Available in MySQL 5.7
◦ Built in since PostgreSQL 12
o Included in DDL
◦ In CREATE or ALTER TABLE
◦ Can be VIRTUAL or STORED

Join
o Display all students and their
courses for 1st semester
o Display all students who doesn’t
take any courses for 1st semester
o Display all courses which nobody
take for 1st semester
o Inner Join
o Left Outer Join
o Right Outer Join

Aggregation
o Display all students and total
course for each students
◦ If any students doesn’t take any
courses, display 0 (zero) instead
o Left Join
o Count()

Subqueries
o Nested query
◦ Query within query
o Derived Tables
o Do’s
◦ Subquery in FROM clause
◦ Subquery in WHERE clause
o Don’t’s
◦ Subquery in SELECT clause

AdvancedQueries LET DATABASE SOLVE
OUR PROBLEMS

AdvanceQueries
oComputed column in query
oGenerated column in table
oJoin and Union
oAggregation
oSubqueries
oCommon Table Expression
oPivot/Crosstab Query
oCalculating Running Totals
oAnalytical Query
oHierarchical Query

CommonTableExpression
o Available in MySQL 8.0+ and PostgreSQL 8.4+
o Temporary result set that exists only within execution scope
o Advantages compared to derived tables
◦ Can be referenced multiple times
◦ Can be self-referencing/recursive
◦ Better readability and performance
o Basic syntax
◦ WITH cte_name (column_list) AS ( query ) SELECT * FROM cte_name;

Pivot/CrosstabQuery
o Convert rows into columns
◦ Simple crosstab, where columns count are known before hand
◦ Dynamic crosstab, where columns dynamically generated in query
o MySQL
◦ Use combination of min/max/sum and group by
◦ Dynamically generate coloumn using group_concat()
o PostgreSQL
◦ You’re lucky.... crosstab() function is already built-in
o Sample data available here.

CalculatingRunningTotals
o Running total
◦ Running balance
◦ Cumulative sum
o Introduce variable to
store total calculation
(MySQL 5.7 and earlier)
o More complex example
available here

AnalyticalQuery
o Revisit running total query
◦ Works on MySQL 8.0 and
PostgreSQL 8.4+
o Windowing function
◦ SUM() OVER()
◦ MIN() OVER()
◦ MAX OVER()
◦ COUNT() OVER()

HierarchicalQuery
o Using recursive (CTE) is a CTE that has a subquery which refers to the CTE
name itself.
o Basic syntax of a recursive CTE
◦ WITH RECURSIVE cte_name AS (
initial_query -- anchor member
UNION ALL recursive_query -- recursive member that references to the CTE name
)
SELECT * FROM cte_name;

References
o PHPID Online Meetup #01
◦ Slide di
https://www.slideshare.net/hidayat365/how-to-
design-a-good-database
◦ Sesi materi di https://youtu.be/pACuwalpQpk
◦ Sesi tanya jawab di https://youtu.be/_OMuPT0-Gv4
o Konsep Database Relasional dan Bahasa SQL
◦ https://pojokprogrammer.net/content/konsep-
database-relasional-dan-bahasa-sql
PHPIDONLINEMEETUP–CODEFACTORY 08/05/2020

Do It With SQL - Journey to the Center of Database Worlds

More Related Content

What's hot (20)

Similar to Do It With SQL - Journey to the Center of Database Worlds (20)

More from Nur Hidayat (6)

Recently uploaded (20)

Do It With SQL - Journey to the Center of Database Worlds