counting comma separated values mysql-postgre - mysql

Question

I have a column called "feedback", and have 1 field called "emotions". In those emotions field, we can see the random values and random length like
emotions
sad, happy
happy, angry, boring
boring
sad, happy, boring, laugh
etc with different values and different length.
so, the question is, what's query to serve the mysql or postgre data:
emotion
count
happy
3
angry
1
sad
2
boring
3
laugh
1
based on SQL: Count of items in comma-separated column in a table we could try using
SELECT value as [Holiday], COUNT(*) AS [Count]
FROM OhLog
CROSS APPLY STRING_SPLIT([Holidays], ',')
GROUP BY value
but it wont help because that is for sql server, not mysql or postgre. or anyone have idea to translation those sqlserver query to mysql?
thank you so much.. I really appreciate it

Answer 1

Using Postgres:
create table emotions(id integer, emotions varchar);
insert into emotions values (1, 'sad, happy');
insert into emotions values (2, 'happy, angry, boring');
insert into emotions values (3, 'boring');
insert into emotions values (4, 'sad, happy, boring, laugh');
select
emotion, count(*)
from
(select
trim(regexp_split_to_table(emotions, ',')) as emotion
from emotions) as t
group by
emotion;
emotion | count
---------+-------
happy | 3
sad | 2
boring | 3
laugh | 1
angry | 1
From String functions regexp_split_to_table will split the string on ',' and return the individual elements as rows. Since there are spaces between the ',' and the word use trim to get rid of the spaces. This then generates a 'table' that is used as a sub-query. In the outer query group by the emotion field and count them.

Answer 2

Try the following using MySQL 8.0:
WITH recursive numbers AS
(
select 1 as n
union all
select n + 1 from numbers where n < 100
)
,
Counts as (
select trim(substring_index(substring_index(emotions, ',', n),',',-1)) as emotions
from Emotions
join numbers
on char_length(emotions) - char_length(replace(emotions, ',', '')) >= n - 1
)
select emotions,count(emotions) as counts from Counts
group by emotions
order by emotions
See a demo from db-fiddle.
The recursive query is to generate numbers from 1 to 100, supposing that the maximum number of sub-strings is 100, you may change this number accordingly.

Answer 3

I've used MySQL 8.0, the query has no string limits. (Thanks to Ahmed for the intuition on recursive clause)
WITH RECURSIVE cte AS (
SELECT ( LENGTH(REGEXP_REPLACE(emotions, ' ?[A-z]+ ?', ''))+1) AS n, emotions AS subs
FROM feedback
UNION ALL
SELECT n-1 AS n, ( SUBSTRING_INDEX(subs, ', ', n-1) ) AS subs
FROM cte
HAVING n>0
)
SELECT SUBSTRING_INDEX(subs, ', ', -1) AS emotions, COUNT(subs) AS cnt
FROM cte
GROUP BY emotions