Getting values from multiple rows into a single row - sql

Question

I want to get the values of multiple rows of a single column to different column in a single row based on the condition of another column.
I want to get the values of the field_value_name in same row but different columns based on values present in the field_name column as they belong to the same id.
How to get this through sql or pyspark?
I tried using CASE WHEN but it will scan for every row and return the output for every row. [
I'd rather want those values to be in a single row for every id.

Answer 1

You need pivoting logic here, e.g.
SELECT
parent_id,
MAX(CASE WHEN properties_field_name = 'Status'
THEN properties_field_value_name END) AS REQ_STATUS,
MAX(CASE WHEN properties_field_name = 'Type'
THEN properties_field_value_name END) AS REQ_TYPE,
MAX(CASE WHEN properties_field_name = 'Description'
THEN properties_field_value_name END) AS REQ_DESC
FROM yourTable
GROUP BY parent_id
ORDER BY parent_id;

Answer 2

You can do it with MAX like Tim shows or you can do it with joins like this:
SELECT
parent_id,
status.properties_field_value_name as status,
type.properties_field_value_name as type,
desc.properties_field_value_name as desc
FROM (
SELECT distinct partent_id
FROM thetableyoudidnotname
) as base
LEFT JOIN thetableyoudidnotname as status on base.parent_id = status.parent_id and status.properties_field_name = 'Status'
LEFT JOIN thetableyoudidnotname as type on base.parent_id = type.parent_id and type.properties_field_name = 'Type'
LEFT JOIN thetableyoudidnotname as desc on base.parent_id = desc.parent_id and desc.properties_field_name = 'Description'

Answer 3

Simple pivot problem I think.
data = [
[7024549, 'Status', 'Approved'],
[7024549, 'Type', 'Jama Design'],
[7024549, 'Description', 'null']
]
df = spark.createDataFrame(data, ['parent_id', 'properties_field_name', 'properties_field_value_name'])
df.withColumn('id', f.expr('uuid()')) \
.withColumn('properties_field_name', f.concat(f.lit('REQ_'), f.upper(f.col('properties_field_name')))) \
.groupBy('id', 'parent_id') \
.pivot('properties_field_name') \
.agg(f.first('properties_field_value_name')) \
.drop('id') \
.show()
+---------+---------------+----------+-----------+
|parent_id|REQ_DESCRIPTION|REQ_STATUS| REQ_TYPE|
+---------+---------------+----------+-----------+
| 7024549| null| Approved| null|
| 7024549| null| null|Jama Design|
| 7024549| null| null| null|
+---------+---------------+----------+-----------+