Find primary key from one table in comma separated list - sql-server

Question

I've been given the task at work of creating a report based on a very poorly designed table structure.
Consider the following two tables. They contain techniques that each person likes to perform at each gym. Keep in mind that a unique person may show up on multiple rows in the PERSONNEL table:
PERSONNEL
+-----+-----+-------+--------+-----------+
| ID | PID | Name | Gym | Technique |
+-----+-----+-------+--------+-----------+
| 1 | 122 | Bob | GymA | 2,3,4 |
+-----+-----+-------+--------+-----------+
| 2 | 131 | Mary | GymA | 1,2,4 |
+-----+-----+-------+--------+-----------+
| 3 | 122 | Bob | GymB | 1,2,3 |
+-----+-----+-------+--------+-----------+
TECHNIQUES
+-----+------------+
| ID | Technique |
+-----+------------+
| 1 | Running |
+-----+------------+
| 2 | Walking |
+-----+------------+
| 3 | Hopping |
+-----+------------+
| 4 | Skipping |
+-----+------------+
What I am having trouble coming up with is a MSSQL query that will reliably give me a listing of every person in the table that is performing a certain technique.
For instance, let's say that I want a listing of every person that likes skipping. The desired results would be:
PREFERS_SKIPPING
+-----+-------+--------+
| PID | Name | Gym |
+-----+-------+--------+
| 122 | Bob | GymA |
+-----+-------+--------+
| 131 | Mary | GymA |
+-----+-------+--------+
Likewise hopping:
PREFERS_HOPPING
+-----+-------+--------+
| PID | Name | Gym |
+-----+-------+--------+
| 122 | Bob | GymA |
+-----+-------+--------+
| 122 | Bob | GymB |
+-----+-------+--------+
I can break out the strings easily in ColdFusion, but that isn't an option due to the size of the PERSONNEL table. Can anyone help?

Answer 1

I think this query looks cleaner:
SELECT p.*,
t.Technique as ParsedTechnique
FROM Personnel p
JOIN Techniques t
ON CHARINDEX((','+CAST(t.id as varchar(10))+','), (','+p.technique+',')) > 0
WHERE t.id ='1';
You can just change the WHERE t.id = to whatever TechniqueId you need.
Fiddle Here

Answer 2

Using this function
Create FUNCTION F_SplitAsIntTable
(
#txt varchar(max)
)
RETURNS
#tab TABLE
(
ID int
)
AS
BEGIN
declare #i int
declare #s varchar(20)
Set #i = CHARINDEX(',',#txt)
While #i>1
begin
set #s = LEFT(#txt,#i-1)
insert into #tab (id) values (#s)
Set #txt=RIGHT(#txt,Len(#txt)-#i)
Set #i = CHARINDEX(',',#txt)
end
insert into #tab (id) values (#txt)
RETURN
END
You can query like this
declare #a Table (id int,Name varchar(10),Kind Varchar(100))
insert into #a values (1,'test','1,2,3,4'),(2,'test2','1,2,3,5'),(3,'test3','3,5')
Select a.ID,Name
from #a a
cross apply F_SplitAsIntTable(a.Kind) b
where b.ID=2

Answer 3

One of the problems you have to prevent is prevent "1" from matching "10" and "11". For this, you want to be sure that all values are delimited by the separator (in this case a comma).
Here is a method using like that should work effectively (although performance will not be so great):
SELECT p.*, t.Technique as ParsedTechnique
FROM Personnel p join
Techniques t
on ','+p.technique+',' like '%,'+cast(t.id as varchar(255))+',%'
WHERE t.id = 1;
If performance is an issue, then fix your data structure an include a PersonTechniques table so you can do a proper join.

Answer 4

The first comment under the question provided the link to the answer. Here's what I ended up going with:
WHERE
p.Technique LIKE '%,29,%' --middle
OR
p.Technique LIKE '29,%' --start
OR
p.Technique LIKE '%,29' --end
OR
p.Technique = '29' --single (good point by Cheran S in comment)
At initial glance I thought it wouldn't work, but clever use of % made it not match ids like 129, etc.