T-SQL How to convert comma separated string of numbers to integer

Question

I get the error \"Conversion failed when converting the nvarchar value \'23,24,3,45,91,\' to data type int.\" The error seems to be occuring on the ON clause. E.ID is an int

Answer 1

You will either have to normalize the F.LegalIssue into many rows or you would have to use a LIKE

Something like

    CAST(E.ID A VARCHAR(50)) = F.LegalIssue
OR  F.LegalIssue LIKE CAST(E.ID A VARCHAR(50)) + ',%'
OR  '%,' + F.LegalIssue LIKE CAST(E.ID A VARCHAR(50)) + ',%'
OR  '%,' + F.LegalIssue LIKE CAST(E.ID A VARCHAR(50))

As you can see, the actual design of the table is the issue. You should rather avoid the design you have currently, and opt for a 1 to many or many to many design.

Here is a DEMO of how to flatten the values using a recursive CTE

SQL Fiddle DEMO

Creating test table and data

CREATE TABLE Tada(
  ID INT,
  SomeCommaString VARCHAR(50)
  )
INSERT INTO Tada Values (1, '10'),(2,'5,6,12,16')

Flattening the table

;WITH Vals AS (
  SELECT 
      ID,
      CASE
          WHEN CHARINDEX(',',SomeCommaString) = 0
            THEN SomeCommaString
          WHEN CHARINDEX(',',SomeCommaString) > 0
            THEN LEFT(SomeCommaString,CHARINDEX(',',SomeCommaString) - 1)
      END Val,

      CASE
          WHEN CHARINDEX(',',SomeCommaString) > 0
            THEN RIGHT(SomeCommaString,LEN(SomeCommaString) - CHARINDEX(',',SomeCommaString))
          ELSE NULL
      END Remainder
  FROM Tada
  UNION ALL
  SELECT 
      ID,
      CASE
          WHEN CHARINDEX(',',Remainder) = 0
            THEN Remainder
          WHEN CHARINDEX(',',Remainder) > 0
            THEN LEFT(Remainder,CHARINDEX(',',Remainder) - 1)
      END Val,

      CASE
          WHEN CHARINDEX(',',Remainder) > 0
            THEN RIGHT(Remainder,LEN(Remainder) - CHARINDEX(',',Remainder))
          ELSE NULL
      END Remainder

  FROM Vals
  WHERE Remainder IS NOT NULL
)
SELECT ID, Val
FROM Vals

Answer 2

If LegalIssue contains a string of comma-delimited numbers, then you really want an association table. Lacking that, here is a convenient (but not efficient) way to do the join:

SELECT F.[FDTitle], E.PrimaryOpID as [FD Primary OP ID], F.County as [FD County],
       F.Status as [FD Status], F.IssueDate as [FD Date]
FROM [dbo].[tbl_FinalDetMain] F LEFT OUTER JOIN
      [dbo].[tbl_lk_Exemptions_FD] E
      ON ','+F.LegalIssue+',' like '%,'cast(E.ID as varchar(255))+',%'
WHERE F.[FDNbr] = '2013-0041';

This prepends and postpends the list with commas to avoid conflicts, such as finding "10" in "1,100,1000".

Answer 3

Using xml datatype, you can explode your string to integers like this. Good candidate for a user defined function I would say :-)

declare @test varchar(max)

set @test = '1,2,3,4,5'

select 
     T2.item.value('(./text())[1]','int') 
from
     (select convert(xml,'<items><t>'+replace(@test,',','</t><t>')+'</t></items>') as xmldoc)
as xmltable
     CROSS APPLY xmltable.xmldoc.nodes('/items/t') as T2(item)