How to concatenate and sum random comma separated values with case statement? - sql

Question

I have a view which is a simple case statement.
SELECT CAST(
CASE
WHEN [value] = 'Canadian' and fieldid = 78
THEN 5
WHEN [value] = 'US' and fieldid = 78
Then 3
WHEN [value] = 'UK' and fieldid = 78
Then 1
When [value] = 'Australia' and fieldid = 78
Then 1
When [value] = 'Israel' and fieldid = 78
Then 1
When [value] = 'Others' and fieldid = 78
Then 1
Everything is ok so far when a column has the matching value it gives it the point but sometimes the column can hold random multiple values separated by comma. How can i calculate that?
This is what happens now.
+----+------------------+--------+
| ID | Value | Points |
+----+------------------+--------+
| 1 | Canadian | 5 |
| 2 | UK | 1 |
| 3 | Canadian,UK | 0 |
+----+----------+----------------+
Expected result
+----+------------------+--------+
| ID | Value | Points |
+----+------------------+--------+
| 1 | Canadian | 5 |
| 2 | UK | 1 |
| 3 | Canadian,UK | 6 |
+----+----------+----------------+

Answer 1

You can do this just with CASE and LIKE:
SELECT ((CASE WHEN ',' + [value] + ',' LIKE '%,Canadian,%' and fieldid = 78
THEN 5 ELSE 0
END) +
(CASE WHEN ',' + [value] + ',' LIKE '%,US,%' and fieldid = 78
THEN 3 ELSE 0
END) +
(CASE WHEN ',' + [value] + ',' LIKE '%,UK,%' and fieldid = 78
THEN 1 ELSE 0
END) +
(CASE WHEN ',' + [value] + ',' LIKE '%,Australia,%' and fieldid = 78
THEN 1 ELSE 0
END) +
(CASE WHEN ',' + [value] + ',' LIKE '%,Israel,%' and fieldid = 78
THEN 1 ELSE 0
END) +
(CASE WHEN ',' + [value] + ',' LIKE '%,Others,%' and fieldid = 78
THEN 1 ELSE 0
END)
) as val
That said, I strongly, strongly, strongly discourage you from storing multiple values in a single column. SQL is designed to store a single value in columns (at least for the scalar column types and a string is a scalar type).
You should have a separate table that is a junction/association table with one row per entity and country.
EDIT: If you were using SQL Server 2017 or had a split string function, I would advise you to do it this way:
SELECT t.ID, t.[value], COALESCE(s.points, 0) as points
FROM tab t OUTER APPLY
(SELECT SUM(CASE WHEN s.[value] = 'Canadian' THEN 5
WHEN s.[value] = 'US' THEN 3
WHEN s.[value] IN ('UK', 'Australia' , 'Israel', 'Others') THEN 1
END) AS Points
FROM STRING_SPLIT(t.[value], ',') s
WHERE t.fieldid = 78
) s
ORDER BY t.id;

Answer 2

Starting from SQL Server 2017 you could use:
SELECT DISTINCT t.ID, t.[value],
SUM(CASE
WHEN s.[value] = 'Canadian' and fieldid = 78
THEN 5
WHEN s.[value] = 'US' and fieldid = 78
Then 3
WHEN s.[value] = 'UK' and fieldid = 78
Then 1
When s.[value] = 'Australia' and fieldid = 78
Then 1
When s.[value] = 'Israel' and fieldid = 78
Then 1
When s.[value] = 'Others' and fieldid = 78
Then 1
END) OVER(PARTITION BY ID) AS Points
FROM tab t
CROSS APPLY STRING_SPLIT(t.[value], ',') s
ORDER BY t.id;
DBFiddle Demo
Storing multiple values in single column violates 1st Normal Form and it should be avoided.
It could be simplified to:
SELECT DISTINCT t.ID, t.[value],
SUM(CASE
WHEN s.[value] = 'Canadian' and fieldid = 78
THEN 5
WHEN s.[value] = 'US' and fieldid = 78
Then 3
WHEN s.[value] IN ('UK', 'Australia' , 'Israel', 'Others')
and fieldid = 78
Then 1
END) OVER(PARTITION BY ID) AS Points
FROM tab t
CROSS APPLY STRING_SPLIT(t.[value], ',') s
ORDER BY t.id;