How do I split a string so I can access item x?

Question

Using SQL Server, how do I split a string so I can access item x?

Take a string "Hello John Smith". How can I split the string by space and access the item at index 1 which should return "John"?

Answer 1

Pure set-based solution using TVF with recursive CTE. You can JOIN and APPLY this function to any dataset.

create function [dbo].[SplitStringToResultSet] (@value varchar(max), @separator char(1))
returns table
as return
with r as (
    select value, cast(null as varchar(max)) [x], -1 [no] from (select rtrim(cast(@value as varchar(max))) [value]) as j
    union all
    select right(value, len(value)-case charindex(@separator, value) when 0 then len(value) else charindex(@separator, value) end) [value]
    , left(r.[value], case charindex(@separator, r.value) when 0 then len(r.value) else abs(charindex(@separator, r.[value])-1) end ) [x]
    , [no] + 1 [no]
    from r where value > '')

select ltrim(x) [value], [no] [index] from r where x is not null;
go

Usage:

select *
from [dbo].[SplitStringToResultSet]('Hello John Smith', ' ')
where [index] = 1;

Result:

value   index
-------------
John    1

Answer 2

In my opinion you guys are making it way too complicated. Just create a CLR UDF and be done with it.

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;
using System.Collections.Generic;

public partial class UserDefinedFunctions {
  [SqlFunction]
  public static SqlString SearchString(string Search) {
    List<string> SearchWords = new List<string>();
    foreach (string s in Search.Split(new char[] { ' ' })) {
      if (!s.ToLower().Equals("or") && !s.ToLower().Equals("and")) {
        SearchWords.Add(s);
      }
    }

    return new SqlString(string.Join(" OR ", SearchWords.ToArray()));
  }
};

Answer 3

', @Delimiter))) FROM @X.nodes('fn_Split') as X(C) -- Return our temp table RETURN END

Answer 4

Well, mine isn't all that simpler, but here is the code I use to split a comma-delimited input variable into individual values, and put it into a table variable. I'm sure you could modify this slightly to split based on a space and then to do a basic SELECT query against that table variable to get your results.

-- Create temporary table to parse the list of accounting cycles.
DECLARE @tblAccountingCycles table
(
    AccountingCycle varchar(10)
)

DECLARE @vchAccountingCycle varchar(10)
DECLARE @intPosition int

SET @vchAccountingCycleIDs = LTRIM(RTRIM(@vchAccountingCycleIDs)) + ','
SET @intPosition = CHARINDEX(',', @vchAccountingCycleIDs, 1)

IF REPLACE(@vchAccountingCycleIDs, ',', '') <> ''
BEGIN
    WHILE @intPosition > 0
    BEGIN
        SET @vchAccountingCycle = LTRIM(RTRIM(LEFT(@vchAccountingCycleIDs, @intPosition - 1)))
        IF @vchAccountingCycle <> ''
        BEGIN
            INSERT INTO @tblAccountingCycles (AccountingCycle) VALUES (@vchAccountingCycle)
        END
        SET @vchAccountingCycleIDs = RIGHT(@vchAccountingCycleIDs, LEN(@vchAccountingCycleIDs) - @intPosition)
        SET @intPosition = CHARINDEX(',', @vchAccountingCycleIDs, 1)
    END
END

The concept is pretty much the same. One other alternative is to leverage the .NET compatibility within SQL Server 2005 itself. You can essentially write yourself a simple method in .NET that would split the string and then expose that as a stored procedure/function.

Answer 5

This pattern works fine and you can generalize

Convert(xml,'<n>'+Replace(FIELD,'.','</n><n>')+'</n>').value('(/n[INDEX])','TYPE')
                          ^^^^^                                   ^^^^^     ^^^^

note FIELD, INDEX and TYPE.

Let some table with identifiers like

sys.message.1234.warning.A45
sys.message.1235.error.O98
....

Then, you can write

SELECT Source         = q.value('(/n[1])', 'varchar(10)'),
       RecordType     = q.value('(/n[2])', 'varchar(20)'),
       RecordNumber   = q.value('(/n[3])', 'int'),
       Status         = q.value('(/n[4])', 'varchar(5)')
FROM   (
         SELECT   q = Convert(xml,'<n>'+Replace(fieldName,'.','</n><n>')+'</n>')
         FROM     some_TABLE
       ) Q

splitting and casting all parts.

Answer 6

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