Mengenal tipe data dan fitur Redshift

Pengantar Redshift

Jason Myers

Principal Architect

Tipe data dasar

Tipe numerik

SMALLINT, INTEGER, BIGINT
DECIMAL / NUMERIC
DOUBLE PRECISION
REAL

Tipe tanggal/waktu

DATE
TIME, TIMETZ
TIMESTAMP, TIMESTAMPTZ

Tipe karakter

CHAR
VARCHAR

Tipe Boolean

BOOLEAN

Tipe data khusus

Tipe SUPER

Data semiterstruktur
- Array
- Tuple
- Struktur bertingkat (mis. JSON)
Gunakan PartiQL untuk memprosesnya
Ukuran maks 16MB

Tipe VARBYTE

data biner (BLOB)
Gambar dan Video

Tipe PostgreSQL yang tidak didukung:

Tipe PostgreSQL	Tipe Redshift
DATETIME	TIMESTAMP, TIMESTAMPTZ
SERIAL	INTEGER, BIGINT
UUID	VARCHAR
JSON	SUPER, VARCHAR
ARRAY	SUPER, VARCHAR
BIT	BOOLEAN, SMALLINT, VARCHAR

Melihat kolom dan tipe datanya

-- View the column details
SELECT column_name, 
       data_type, 
       character_maximum_length AS character_max_len,
       numeric_precision, 
       numeric_scale
  -- Using a view with both internal and external schema's columns
  FROM SVV_ALL_COLUMNS 
 -- Only in the spectrumdb schema
 WHERE schema_name = 'spectrumdb'
   -- For the ecommerce_sales table
   AND table_name = 'ecommerce_sales';

Melihat kolom dan tipe datanya (lanj.)

column_name                  | data_type         | character_max_len | numeric_precision | numeric_scale
=============================|===================|===================|===================|==============
year_qtr                     | character varying | 100               | null              | null
total_sales                  | integer           | null              | 32                | 0
ecom_sales                   | integer           | null              | 32                | 0
percent_ecom                 | real              | null              | null              | null
percent_change_quarter_total | real              | null              | null              | null
percent_change_quarter_ecom  | real              | null              | null              | null
percent_change_year_total    | real              | null              | null              | null
percent_change_year_ecom     | real              | null              | null              | null

"Kecocokan" tipe data

Konversi implisit: penugasan, perbandingan
Selalu cek hasilnya!

From Type	To Types
CHAR	VARCHAR
DATE	CHAR, VARCHAR, TIMESTAMP, TIMESTAMPTZ
TIMESTAMP	CHAR, DATE, VARCHAR, TIMESTAMPTZ
BIGINT	BOOLEAN, CHAR, DECIMAL, DOUBLE PRECISION, INTEGER, REAL, SMALLINT, VARCHAR
DECIMAL	BIGINT, CHAR, DOUBLE PRECISION, INTEGER, REAL, SMALLINT, VARCHAR

¹ https://docs.aws.amazon.com/redshift/latest/dg/c_Supported_data_types.html#r_Type_conversion

Casting tipe data secara eksplisit

CAST

-- Casting a decimal to a integer and aliasing it
SELECT CAST(2.00 AS INTEGER) AS our_int;

our_int
========
2
(1 row)

Fungsi TO

TO_CHAR, TO_DATE, TO_NUMBER

-- Convert the string to a date
SELECT CAST('14-01-2024 02:36:48' AS DATE) AS out_date;

date/time field value out of range: "14-01-2024 02:36:48"
HINT:  Perhaps you need a different "datestyle" setting.

-- Parse the string to a date
SELECT TO_DATE('14-01-2024 02:36:48', 'DD-MM-YYYY') AS our_date;

our_date
========
2024-01-14
(1 row)

Fungsi TO (lanj.)

-- Get the name of the month in a date
SELECT TO_CHAR(date '2024-01-14', 'MONTH') AS month_name;

month_name
========
JANUARY
(1 row)

String format Tanggal/Waktu dan Numerik

¹ https://docs.aws.amazon.com/redshift/latest/dg/r_FORMAT_strings.html

Ayo berlatih!

Pengantar Redshift