Split a string into 3 columns - with a twist - sql

Question

I have a very long text string being imported into a table. I would like to split the string up; I have a routine to pull the data into a table, but it creates all the data in a single field in a table.
Example Text:
05/10/2018 21:14,#FXAAF00123456,,Cup 1 X Plane,0.00000,OK,Cup 1 Y Plane,0.00000,OK,Cup 1 Z Plane,40.64252,OK,Cup 2 X Plane,77.89434,OK,..etc
(The test string is much longer than this, in the region of 1500-1700 characters, but with the same structure in the rest of the string).
This data is a series of test measurements, with the name of the value, the value, and the OK/NOK indicator.
I want the results to be stored in a table (variable) with three fields, so the data above becomes:
Field1|Field2|Field3
05/10/2018 21:14|#FXAAF00123456|null|
Cup 1 X Plane|0.00000|OK|
Cup 1 Y Plane|0.00000|OK|
Cup 1 Z Plane|40.64252|OK|
Cup 2 X Plane|77.89434|OK|
...etc
I am using this function to split the string into a table variable:
CREATE FUNCTION [dbo].[fnSplitString]
(
#InputString NVARCHAR(MAX),
#Delim VARCHAR(255)
)
RETURNS TABLE
AS
RETURN ( SELECT [Value] FROM
(
SELECT
[Value] = LTRIM(RTRIM(SUBSTRING(#InputString, [Number],
CHARINDEX(#Delim, #InputString + #Delim, [Number]) - [Number])))
FROM (SELECT Number = ROW_NUMBER() OVER (ORDER BY name)
FROM sys.all_objects) AS x
WHERE Number <= LEN(#InputString)
AND SUBSTRING(#Delim + #InputString, [Number], LEN(#Delim)) = #Delim
) AS y
);
How can this be modified to give the output required above?

Answer 1

You can try this tiny inline splitting approach.
DECLARE #s VARCHAR(MAX)='05/10/2018 21:14,#FXAAF00123456,,Cup 1 X Plane,0.00000,OK,Cup 1 Y Plane,0.00000,OK,Cup 1 Z Plane,40.64252,OK,Cup 2 X Plane,77.89434,OK';
;WITH
a AS (SELECT n=0, i=-1, j=0 UNION ALL SELECT n+1, j, CAST(CHARINDEX(',', #s, j+1) AS INT) FROM a WHERE j > i)
,b AS (SELECT n, SUBSTRING(#s, i+1, IIF(j>0, j, LEN(#s)+1)-i-1) s FROM a WHERE i >= 0)
,c AS (SELECT n,(n-1) % 3 AS Position,(n-1)/3 AS RowIndex,s FROM b)
SELECT MAX(CASE WHEN Position=0 THEN s END) AS part1
,MAX(CASE WHEN Position=1 THEN s END) AS part2
,MAX(CASE WHEN Position=2 THEN s END) AS part3
FROM c
GROUP BY RowIndex
OPTION (MAXRECURSION 0);
The result
part1 part2 part3
05/10/2018 21:14 #FXAAF00123456
Cup 1 X Plane 0.00000 OK
Cup 1 Y Plane 0.00000 OK
Cup 1 Z Plane 40.64252 OK
Cup 2 X Plane 77.89434 OK
Hint
You might change your splitter function to the recursive approach above. On the one side you are limited to a string-length of the count in sys.all_objects which might be smaller than your input. On the other side your approach has to test each and any position, while the recursive approach hops from spot to spot. Should be faster...
This could easily be opened for a multi-character-delimiter if needed...
UPDATE another approach without recursion
...which makes it clumsy to be used in a splitter function (due to OPTION MAXRECURSION(0), which must be placed at the end of the query and cannot live within the function). Try it out:
;WITH
a(Casted) AS (SELECT CAST('<x>' + REPLACE((SELECT #s AS [*] FOR XML PATH('')),',','</x><x>') + '</x>' AS XML))
,b(s,RowIndex,Position) AS
(
SELECT x.value(N'text()[1]','nvarchar(max)')
,(ROW_NUMBER() OVER(ORDER BY(SELECT NULL)) -1) /3
,(ROW_NUMBER() OVER(ORDER BY(SELECT NULL)) -1) %3
FROM a
CROSS APPLY Casted.nodes(N'/x') X(x)
)
SELECT RowIndex
,MAX(CASE WHEN Position=0 THEN s END) AS part1
,MAX(CASE WHEN Position=1 THEN s END) AS part2
,MAX(CASE WHEN Position=2 THEN s END) AS part3
FROM b
GROUP BY RowIndex;
Hint:
Using (SELECT #s AS [*] FOR XML PATH('')) will make this approach save with forbidden characters...

Answer 2

this required a small modification to your fnSplitString function. Add a RowNo to identify the original sequence of the delimited item
CREATE FUNCTION [dbo].[fnSplitString]
(
#InputString NVARCHAR(MAX),
#Delim VARCHAR(255)
)
RETURNS TABLE
AS
RETURN ( SELECT [Value] FROM
(
SELECT RowNo = ROW_NUMBER() OVER (ORDER BY Number),
[Value] = LTRIM(RTRIM(SUBSTRING(#InputString, [Number],
CHARINDEX(#Delim, #InputString + #Delim, [Number]) - [Number])))
FROM (SELECT Number = ROW_NUMBER() OVER (ORDER BY name)
FROM sys.all_objects) AS x
WHERE Number <= LEN(#InputString)
AND SUBSTRING(#Delim + #InputString, [Number], LEN(#Delim)) = #Delim
) AS y
);
And with that, you can group every 3 rows as one. Also the RowNo can be used to identify the column
The query
; with tbl as
(
select col = '05/10/2018 21:14,#FXAAF00123456,,Cup 1 X Plane,0.00000,OK,Cup 1 Y Plane,0.00000,OK,Cup 1 Z Plane,40.64252,OK,Cup 2 X Plane,77.89434,OK'
)
select Field1 = MAX(CASE WHEN (RowNo - 1) % 3 = 0 THEN Value END),
Field2 = MAX(CASE WHEN (RowNo - 1) % 3 = 1 THEN Value END),
Field3 = MAX(CASE WHEN (RowNo - 1) % 3 = 2 THEN Value END)
from tbl t
cross apply dbo.fnSplitString (t.col, ',')
group by (RowNo - 1) / 3

Answer 3

Can you try following script after you create the SQL split function given in the reference document.
That split function returns the order of splitted string fragments so that information is used for row data
declare #str nvarchar(max) = '05/10/2018 21:14,#FXAAF00123456,,Cup 1 X Plane,0.00000,OK,Cup 1 Y Plane,0.00000,OK,Cup 1 Z Plane,40.64252,OK,Cup 2 X Plane,77.89434,OK'
select
floor(id / 3)+1 rn,
case when id % 3 = 1 then val end Field1,
case when id % 3 = 2 then val end Field2,
case when id % 3 = 0 then val end Field3
from dbo.Split(#str,',')
select
rn,
max(Field1) Field1,
max(Field2) Field2,
max(Field3) Field3
from (
select
floor((id-1) / 3)+1 rn,
case when id % 3 = 1 then val end Field1,
case when id % 3 = 2 then val end Field2,
case when id % 3 = 0 then val end Field3
from dbo.Split(#str,',')
) t
group by rn