Split string and select into new table - sql

Question

I have a table with a structure like this
ID pointCount pointSeries
1 282 35.1079,-111.0151,35.1088,-111.0196...
Obviously the point series is string has pair of lat lon as points. I want to select the pointSeries into a new table
ID Lat Lon
1 35.1079 -111.0151
1 35.1088 -111.0196
What's the best way I can do a split and select into query?

Answer 1

You need to have a function for splitting comma-delimited strings into separate rows. Here is the DelimitedSplit8K function by Jeff Moden.
CREATE FUNCTION [dbo].[DelimitedSplit8K](
#pString NVARCHAR(4000), #pDelimiter NCHAR(1)
)
RETURNS TABLE WITH SCHEMABINDING AS
RETURN
WITH E1(N) AS (
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
)
,E2(N) AS (SELECT 1 FROM E1 a, E1 b)
,E4(N) AS (SELECT 1 FROM E2 a, E2 b)
,cteTally(N) AS(
SELECT TOP (ISNULL(DATALENGTH(#pString),0)) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
)
,cteStart(N1) AS(
SELECT 1 UNION ALL
SELECT t.N+1 FROM cteTally t WHERE SUBSTRING(#pString,t.N,1) = #pDelimiter
),
cteLen(N1,L1) AS(
SELECT
s.N1,
ISNULL(NULLIF(CHARINDEX(#pDelimiter,#pString,s.N1),0)-s.N1,8000)
FROM cteStart s
)
SELECT
ItemNumber = ROW_NUMBER() OVER(ORDER BY l.N1),
Item = SUBSTRING(#pString, l.N1, l.L1)
FROM cteLen l
Then you need to pivot the result of the split to achieve the desired result:
;WITH CteSplitted AS(
SELECT
t.ID,
x.ItemNumber,
Item = CAST(x.Item AS NUMERIC(16,4)),
RN = (ROW_NUMBER() OVER(PARTITION BY ID ORDER BY ItemNumber) + 1) / 2
FROM Test t
CROSS APPLY dbo.DelimitedSplit8K(t.PointSeries, ',') x
)
SELECT
ID,
Lat = MAX(CASE WHEN ItemNumber % 2 = 1 THEN Item END),
Lon = MAX(CASE WHEN ItemNumber % 2 = 0 THEN Item END)
FROM CteSplitted
GROUP BY ID, RN