Query Split string into rows - sql

Question

I have a table that looks like this:
ID Value
1 1,10
2 7,9
I want my result to look like this:
ID Value
1 1
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
2 7
2 8
2 9
I'm after both a range between 2 numbers with , as the delimiter (there can only be one delimiter in the value) and how to split this into rows.

Answer 1

Splitting the comma separated numbers is a small part of this problem. The parsing should be done in the application and the range stored in separate columns. For more than one reason: Storing numbers as strings is a bad idea. Storing two attributes in a single column is a bad idea. And, actually, storing unsanitized user input in the database is also often a bad idea.
In any case, one way to generate the list of numbers is to use a recursive CTE:
with t as (
select t.*, cast(left(value, charindex(',', value) - 1) as int) as first,
cast(substring(value, charindex(',', value) + 1, 100) as int) as last
from table t
),
cte as (
select t.id, t.first as value, t.last
from t
union all
select cte.id, cte.value + 1, cte.last
from cte
where cte.value < cte.last
)
select id, value
from cte
order by id, value;
You may need to fiddle with the value of MAXRECURSION if the ranges are really big.

Answer 2

Any table that a field with multiple values such as this is a problem in terms of design. The only way to deal with these records as it is is to split the values on the delimiter and put them into a temporary table, implement custom splitting code, integrate a CTE as noted, or redesign the original table to put the comma-delimited fields into separate fields, eg
ID LOWLIMIT HILIMIT
1 1 10

Answer 3

similar with Gordon Linoff variant, but has some difference
--create temp table for data sample
DECLARE #Yourdata AS TABLE ( id INT, VALUE VARCHAR(20) )
INSERT #Yourdata
( id, VALUE )
VALUES ( 1, '1,10' ),
( 2, '7,9' )
--final query
;WITH Tally
AS ( SELECT MIN(CONVERT(INT, SUBSTRING(y.VALUE, 1, CHARINDEX(',', y.value) - 1))) AS MinV ,
MAX(CONVERT(INT, SUBSTRING(y.VALUE, CHARINDEX(',', y.value) + 1, 18))) AS MaxV
FROM #yourdata AS y
UNION ALL
SELECT MinV = MinV + 1 , MaxV
FROM Tally
WHERE MinV < Maxv
)
SELECT y.id , t.minV AS value
FROM #yourdata AS y
JOIN tally AS t ON t.MinV BETWEEN CONVERT(INT, SUBSTRING(y.VALUE, 1, CHARINDEX(',', y.value) - 1))
AND CONVERT(INT, SUBSTRING(y.VALUE, CHARINDEX(',', y.value) + 1, 18))
ORDER BY id, minV
OPTION ( MAXRECURSION 999 ) --change it if required
output