split alpha and numeric using sql

If the numeric part is always at the beginning, then you can use this:

PATINDEX('%[0-9][^0-9]%', ConcUnit)

to get the index of the last digit.

Thus, this:

DECLARE @str VARCHAR(MAX) = '4000 ug/ML' SELECT LEFT(@str, PATINDEX('%[0-9][^0-9]%', @str )) AS Number,       LTRIM(RIGHT(@str, LEN(@str) - PATINDEX('%[0-9][^0-9]%', @str ))) As Unit

gives you:

Number  Unit-------------4000    ug/ML

EDIT:

If numeric data include double values as well, then you can use this:

SELECT LEN(@str) - PATINDEX ('%[^0-9][0-9]%', REVERSE(@str))

to get the index of the last digit.

Thus, this:

SELECT LEFT(@str, LEN(@str) - PATINDEX ('%[^0-9][0-9]%', REVERSE(@str)))

gives you the numeric part.

And this:

SELECT LEFT(@str, LEN(@str) - PATINDEX ('%[^0-9][0-9]%', REVERSE(@str))) AS Numeric,       CASE           WHEN CHARINDEX ('%', @str) <> 0 THEN LTRIM(RIGHT(@str, LEN(@str) - CHARINDEX ('%', @str)))          ELSE LTRIM(RIGHT(@str, PATINDEX ('%[^0-9][0-9]%', REVERSE(@str))))       END AS Unit

gives you both numberic and unit part.

Here are some tests that I made with the data you have posted:

Input:

DECLARE @str VARCHAR(MAX) = '50 000ug/ML'

Output:

Numeric Unit------------50 000  ug/ML

Input:

DECLARE @str VARCHAR(MAX) = '99.5%'

Output:

Numeric Unit------------99.5    

Input:

DECLARE @str VARCHAR(MAX) = '4000 . 35 % ug/ML'

Output:

Numeric     Unit------------------4000 . 35   ug/ML

Here is my answer. Check output in SQLFiddle for the same.

create TABLE temp(      string NVARCHAR(50))INSERT INTO temp (string)VALUES     ('4000 ug\ml'),    ('2000 ug\ml'),    ('%'),    ('ug\ml')SELECT subsrtunit,LEFT(subsrtnumeric, PATINDEX('%[^0-9]%', subsrtnumeric+'t') - 1)FROM (    SELECT subsrtunit = SUBSTRING(string, posofchar, LEN(string)),  subsrtnumeric = SUBSTRING(string, posofnumber, LEN(string))    FROM (        SELECT string, posofchar = PATINDEX('%[^0-9]%', string),      posofnumber = PATINDEX('%[0-9]%', string)        FROM temp    ) d) t

Updated Version to handle 99.5 ug\ml

create TABLE temp(      string NVARCHAR(50))INSERT INTO temp (string)VALUES     ('4000 ug\ml'),    ('2000 ug\ml'),    ('%'),    ('ug\ml'),    ('99.5 ug\ml')SELECT subsrtunit,LEFT(subsrtnumeric, PATINDEX('%[^0-9.]%', subsrtnumeric+'t') - 1)FROM (    SELECT subsrtunit = SUBSTRING(string, posofchar, LEN(string)),  subsrtnumeric = SUBSTRING(string, posofnumber, LEN(string))    FROM (        SELECT string, posofchar = PATINDEX('%[^0-9.]%', string),      posofnumber = PATINDEX('%[0-9.]%', string)        FROM temp    ) d) t

Updated Version: To handle 1 000 ug\ml,20 000ug\ml

create TABLE temp(      string NVARCHAR(50))INSERT INTO temp (string)VALUES     ('4000 ug\ml'),    ('2000 ug\ml'),    ('%'),    ('ug\ml'),    ('99.5 ug\ml'),    ('1 000 ug\ml'),    ('20 000ug\ml')SELECT substring(replace(subsrtunit,' ',''),PATINDEX('%[0-9.]%', replace(subsrtunit,' ',''))+1,len(subsrtunit)),LEFT(replace(subsrtnumeric,' ',''), PATINDEX('%[^0-9.]%', replace(subsrtnumeric,' ','')+'t') - 1)FROM (    SELECT subsrtunit = SUBSTRING(string, posofchar, LEN(string)),  subsrtnumeric = SUBSTRING(string, posofnumber, LEN(string))    FROM (        SELECT string, posofchar = PATINDEX('%[^0-9.]%', replace(string,' ','')),      posofnumber = PATINDEX('%[0-9.]%', replace(string,' ',''))        FROM temp    ) d) t

Check out SQLFiddle for the same.

Would something like this work? Based on the shown data it looks like it would.

Apply it to your data set as a select and if you like the results then you can make an update from it.

WITH cte as (SELECT 'ug/mL' ConcUnit, 500 as [Numeric], '' as Unit    UNION ALL SELECT '2000 ug/mL',     NULL,             '')SELECT    [ConcUnit]                  as [ConcUnit],    [Numeric]                   as [Original Numeric],    [Unit]                      as [Original Unit],    CASE WHEN ConcUnit LIKE '% %' THEN         SUBSTRING(ConcUnit, 1, CHARINDEX(' ', ConcUnit) - 1)         ELSE [Numeric] END      as [New Numeric],    CASE WHEN ConcUnit LIKE '% %'         THEN SUBSTRING(ConcUnit, CHARINDEX(' ', ConcUnit) + 1, LEN(ConcUnit))         ELSE ConcUnit END       as [New Unit]FROM cte