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SQL - Sort order of string with numbers in

Posted on 2011-03-03
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Last Modified: 2012-05-11
I have a table with a list of parts with codes like:-

9f99
9f100
9f101
...
9f1001

etc.

I want to be able to sort these in the order above - a string field will sort the 100 before the 99.

It is possible that the format of these code may change i.e. could be 2 alpha characters in the code.

I thought there may be a way to convert the letters to a 2 digit number 01 - 26 and replace them so I get a number to sort on. In this way all similar codes would be in the right order?

Appreciate any ideas on this.
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Question by:donhannam
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10 Comments
 
LVL 41

Expert Comment

by:Sharath
ID: 35032883
If it always start with 2 alpha characters, you can strip off those 2 character, convert to Int and sort.
select code
  from your_table 
 order by CONVERT(int,SUBSTRING(code,3,LEN(code)))

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LVL 6

Expert Comment

by:judgeking
ID: 35033019
You can do it by creating a function in SQL server that returns the numeric part, then sorts by that.  If you create the GetCodeValue function below, then you could sort your data like this:

SELECT  * FROM Parts ORDER BY dbo.GetCodeValue(code), code
CREATE FUNCTION [dbo].[GetCodeValue](@Code nvarchar(100))
RETURNS int
AS
BEGIN
    DECLARE @iCounter int
    DECLARE @iLen int
    DECLARE @iFound int
    DECLARE @iCodeValue int
    DECLARE @sChar nvarchar(1)

    SET @iLen = LEN(@Code)
    SET @iFound = 0
    SET @iCodeValue = 0

    IF @iLen > 0
    BEGIN
      SET @iCounter = @iLen
      WHILE @iFound = 0 AND @iCounter >= 1
      BEGIN
        SET @sChar = SUBSTRING(@Code, @iCounter, 1)

        IF ISNUMERIC(@sChar) = 1
          SET @iCounter = @iCounter - 1
        ELSE
          SET @iFound = 1
      END

      IF @iFound = 1
      BEGIN
        SET @iCodeValue = CAST(SUBSTRING(@Code, @iCounter + 1, @iLen - @iCounter) AS int)
      END
    END

    RETURN @iCodeValue
END

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LVL 22

Expert Comment

by:Thomasian
ID: 35033287
You can sort by the first 2 alphanumeric characters first, then sort the reset as numbers.
SELECT *
FROM tablename
ORDER BY LEFT(fieldname,2), CAST(SUBSTRING(fieldname,3,1000) as int)

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Author Comment

by:donhannam
ID: 35033371
Thanks for comments - issue is I need to sort by numeric then alpha then numeric and carn't be sure of exact number of characters between each.

judgeking: I think your solution is the best using a function - at present it strips off all characters before and including the last alpha character.

This would work if when it found a character it could replace with a 2 digit number.

I think I can work out the code to do this now and guess I could go case A = '01', B = '02' etc but is there a function to convert characters into there repespective numbers?.
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LVL 22

Accepted Solution

by:
Thomasian earned 500 total points
ID: 35033439
I don't see how replacing a character with a 2-digit number would solve the issue but here's a query which would do that
DECLARE @t table (code nchar(10))

INSERT @t (code)
SELECT '9f99'
UNION ALL SELECT '9f100'
UNION ALL SELECT '9f101'
UNION ALL SELECT '2vs250'
UNION ALL SELECT 'cx120'
UNION ALL SELECT '1as205'

;WITH CTE AS(
  SELECT REPLACE(code,'A','01') newcode, code ,1 n FROM @t
  UNION ALL
  SELECT REPLACE(newcode, CHAR(65 + n) , RIGHT('0' + CAST(n+1 as varchar),2)) newcode, code ,n+1 FROM CTE
  WHERE n < 26
)
SELECT newcode,code
FROM CTE
WHERE n=26
/*
newcode     code
10119205    1as205
107120      1g120
22219250    2vs250
905100      9e100
90699       9f99
*/

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0
 

Author Closing Comment

by:donhannam
ID: 35033474
Thanks - In the format that is required this works perfectly.
0
 
LVL 6

Expert Comment

by:judgeking
ID: 35033762
donhannam, replacing the alpha with numeric makes no sense at all, I'd like you to explain why you wanted that.
0
 

Author Comment

by:donhannam
ID: 35041706
Judgeking

In this case all items that need to be grouped together are in the same format i.e. same number of digits. When we replace the alpha with numeric ends up in the right order i.e 9f99 is before 9f100 and 34ft24 is before 34ft120. I use an additional sort to get the parts in groups.
0
 
LVL 6

Expert Comment

by:judgeking
ID: 35085925
I guess you don't know much about SQL, no need to convert the alpha chars, SQL can sort by either or both.  My code and select statement above would have done exactly what you want in a more elegant and flexible way.  I think I deserved at least an assist on that, I spent quite a bit of time on it.  I don't answer questions just for fun, I need to get a certain amount per month or lose my membership.
0
 

Author Comment

by:donhannam
ID: 35087136
judgeking:

Appoligies - I though you did both posts and allocated points to last one.

I probably would have allocated points between both if I had realised but I don't think I can go back and change now and actually the result I gave points to was the one that worked for me - note it did require conversion of the alpha characters to work properly.
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