-- splitting a string (SQL Server 2016+) SELECT * FROM STRING_SPLIT('100001::M:black:', ':')
The table-valued function object allowed also earlier to implement the same functionality, either by looping through the string or by using a common table expression. Here’s the implementation based on a loop (it was modified from a previous version to include an index):
-- split table-valued function with an index CREATE FUNCTION [dbo].[SplitListWithIndex]( @ListValues varchar(500) , @Delimiter char(1)) RETURNS @Temp TABLE( Ind int , Value varchar(50)) AS BEGIN DECLARE @Index int DECLARE @Length int DECLARE @Ind int SET @Index = CharIndex(@Delimiter, @ListValues) SET @Length = Len(@ListValues) - @Index SET @Ind = 1 WHILE @Index > 0 --if the fatch was successful BEGIN INSERT @Temp VALUES(@Ind, Substring(@ListValues, 0, @Index)) SET @ListValues = Substring(@ListValues, @Index+1, @Length) SET @Index = CharIndex(@Delimiter, @ListValues) SET @Length = @Length - @Index SET @Ind = @Ind + 1 END INSERT @Temp VALUES(@Ind, @ListValues) RETURN END GO
The function could be called in code same as the STRING_SPLIT:
-- splitting a string (SQL Server 2000+) SELECT * FROM dbo.SplitListWithIndex('100001::M:black:', ':')
The two functions are helpful when a column stores delimited values. It’s the case of Dynamics 365 which stores a SKU (Stock Keeping Unit) – the Product Numbers together with its Dimensions (ItemId, Configid, InventSizeId, InventColorId, StyleId) delimited by “:”, like in the above examples. Therefore, to parse the records one could write such code:
-- parsing delimited values (SQL Server 2000+) SELECT DAT.ProductNumber , Max(CASE WHEN LV.Ind = 1 THEN LV.Value END) ItemId , Max(CASE WHEN LV.Ind = 2 THEN LV.Value END) Configid , Max(CASE WHEN LV.Ind = 3 THEN LV.Value END) InventSizeId , Max(CASE WHEN LV.Ind = 4 THEN LV.Value END) InventColorId , Max(CASE WHEN LV.Ind = 5 THEN LV.Value END) StyleId FROM ( VALUES ('100001::S:black:') , ('100001::M:black:') , ('100001::L:black:') , ('100001::XL:black:') , ('100001::S:white:') , ('100001::M:white:') , ('100001::L:white:') , ('100001::XL:white:') ) DAT (ProductNumber) CROSS APPLY dbo.SplitListWithIndex(DAT.ProductNumber, ':') LV GROUP BY DAT.ProductNumber ORDER BY DAT.ProductNumber
-- parsing delimited values (SQL Server 2016+) SELECT LV.ProductNumber , Max(CASE WHEN LV.Ind = 1 THEN LV.Value END) ItemId , Max(CASE WHEN LV.Ind = 2 THEN LV.Value END) Configid , Max(CASE WHEN LV.Ind = 3 THEN LV.Value END) InventSizeId , Max(CASE WHEN LV.Ind = 4 THEN LV.Value END) InventColorId , Max(CASE WHEN LV.Ind = 5 THEN LV.Value END) StyleId FROM ( SELECT DAT.ProductNumber , XT.VALUE , ROW_NUMBER() OVER (PARTITION BY DAT.ProductNumber ORDER BY DAT.ProductNumber) Ind FROM ( VALUES ('100001::S:black:') , ('100001::M:black:') , ('100001::L:black:') , ('100001::XL:black:') , ('100001::S:white:') , ('100001::M:white:') , ('100001::L:white:') , ('100001::XL:white:') ) DAT (ProductNumber) CROSS APPLY STRING_SPLIT(DAT.ProductNumber, ':') XT ) LV GROUP BY LV.ProductNumber ORDER BY LV.ProductNumber
As can be seen the introduction of an index into the dbo.SplitListWithIndex function simplified the code, making the use of a ranking window function unnecessary. It would be useful for the STRING_SPLIT to provide the same, as this time of processing is pretty common.
Here’s another example based on the PIVOT clause introduced also in SQL 2005:
-- parsing delimited values (SQL Server 2016+) SELECT P.ProductNumber , Cast(Trim([1]) as nvarchar(20)) ItemId , Cast(Trim([2]) as nvarchar(20)) ConfigId , Cast(Trim([3]) as nvarchar(20)) InventSizeid , Cast(Trim([4]) as nvarchar(20)) InventColorId , Cast(Trim([5]) as nvarchar(20)) StyleId FROM ( SELECT DAT.ProductNumber , XT.VALUE , ROW_NUMBER() OVER (PARTITION BY DAT.ProductNumber ORDER BY DAT.ProductNumber) Ranking FROM ( VALUES ('100001::S:black:') , ('100001::M:black:') , ('100001::L:black:') , ('100001::XL:black:') , ('100001::S:white:') , ('100001::M:white:') , ('100001::L:white:') , ('100001::XL:white:') ) DAT (ProductNumber) CROSS APPLY STRING_SPLIT(DAT.ProductNumber, ':') XT ) DAT PIVOT (MAX(DAT.[VALUE]) FOR DAT.Ranking IN ([1],[2],[3],[4],[5])) P
Happy coding!
No comments:
Post a Comment