How to convert or transpose rows to columns in SQL without using pivot?

Question

I have faced one issue while getting data transposed in SQL. for eg table given below

id	source_name	value
1	cp	x
1	cp	y
1	hi	a
2	li	b
2	cp	c
2	li	d
3	li	e

I need this table in below format (transposed but with string aggregation)-

id	cp	hi	li	mi
1	x,y	a	null	null
2	c	null	b,d	null
3	null	null	null	d

With the current sql query, I am getting table in below format.

id	cp	hi	li	mi
1	x	a	null	null
2	c	null	b	null
3	null	null	null	d

Can anyone tweak the query or suggest new query in SQL (Platform - Bigquery)?

Current query -

select id, any_value(if(source_name = 'cp', value, null)) as cp,
any_value(if(source_name = 'hi', value, null)) as hi,
any_value(if(source_name = 'li', value, null)) as li
any_value(if(source_name = 'mi', value, null)) as mi
from table_name group by id

Answer 1

Try STRING_AGG instead of any_value :

select id, string_agg(if(source_name = 'cp', value, null)) as cp,
string_agg(if(source_name = 'hi', value, null)) as hi,
string_agg(if(source_name = 'li', value, null)) as li
string_agg(if(source_name = 'mi', value, null)) as mi
from table_name group by id

Answer 2

Use PIVOT operator instead

select *
from `project.dataset.table`
pivot (string_agg(value) for source_name in ('cp', 'hi', 'li', 'mi'))    

If applied to sample data in your question

output is

Check out https://stackoverflow.com/a/67479622/5221944 if you want to make it dynamically build list of columns for you