Data Type Conversion¶

Let us understand how we can type cast to change the data type of extracted value to its original type.

Let us start spark context for this Notebook so that we can execute the code provided. You can sign up for our 10 node state of the art cluster/labs to learn Spark SQL using our unique integrated LMS.

val username = System.getProperty("user.name")

import org.apache.spark.sql.SparkSession

val username = System.getProperty("user.name")
val spark = SparkSession.
    builder.
    config("spark.ui.port", "0").
    config("spark.sql.warehouse.dir", s"/user/${username}/warehouse").
    enableHiveSupport.
    appName(s"${username} | Spark SQL - Predefined Functions").
    master("yarn").
    getOrCreate

If you are going to use CLIs, you can use Spark SQL using one of the 3 approaches.

Using Spark SQL

spark2-sql \
    --master yarn \
    --conf spark.ui.port=0 \
    --conf spark.sql.warehouse.dir=/user/${USER}/warehouse

Using Scala

spark2-shell \
    --master yarn \
    --conf spark.ui.port=0 \
    --conf spark.sql.warehouse.dir=/user/${USER}/warehouse

Using Pyspark

pyspark2 \
    --master yarn \
    --conf spark.ui.port=0 \
    --conf spark.sql.warehouse.dir=/user/${USER}/warehouse

%%sql

SELECT current_date AS current_date

%%sql

SELECT split(current_date, '-')[1] AS month

%%sql

SELECT cast(split(current_date, '-')[1] AS INT) AS month

%%sql

SELECT cast('0.04' AS FLOAT) AS result

%%sql

SELECT cast('0.04' AS INT) AS zero

%%sql

SELECT cast('xyz' AS INT) AS returns_null

%%sql

CREATE EXTERNAL TABLE IF NOT EXISTS orders_single_column (
    s STRING
) LOCATION '/user/itversity/warehouse/itversity_retail.db/orders'

%%sql

SELECT * FROM orders_single_column LIMIT 10

%%sql

SELECT split(s, ',')[0] AS order_id,
    split(s, ',')[1] AS order_date,
    split(s, ',')[2] AS order_customer_id,
    split(s, ',')[3] AS order_status
FROM orders_single_column LIMIT 10

%%sql

SELECT cast(split(s, ',')[0] AS INT) AS order_id,
    cast(split(s, ',')[1] AS TIMESTAMP) AS order_date,
    cast(split(s, ',')[2] AS INT) AS order_customer_id,
    cast(split(s, ',')[3] AS STRING) AS order_status
FROM orders_single_column LIMIT 10

Apache Spark using SQL

Data Type Conversion¶