How to trim/replace any letters in the value? - sql

Question

I have few columns in my old database that have values where number and letters are combined together. This is something that I have to clean and import in the new table. The most of the values that need to be converted look like this:
40M or 85M or NR or 5NR ...
Since there wasn't any validation what user can enter in the old system there still can be values like: 40A or 3R and so on. I want to import only numeric values in my new table. So if there is any letters in the value I want to trim them. What is the best way to do that in SQL Server? I have tried this:
CASE WHEN CHARINDEX('M',hs_ptr1) <> 0 THEN 1 ELSE 0 END AS hs_ptr1
but this will only identify if one letter is in the value. If anyone can help please let me know. Thanks!

Answer 1

you can use patindex to search for the pattern. Try this code:
Code:
CREATE TABLE #temp
(
TXT NVARCHAR(50)
)
INSERT INTO #temp (TXT)
VALUES
('40M'),
('85M'),
('NR'),
('5NR')
SELECT LEFT(subsrt, PATINDEX('%[^0-9]%', subsrt + 't') - 1)
FROM (
SELECT subsrt = SUBSTRING(TXT, pos, LEN(TXT))
FROM (
SELECT TXT, pos = PATINDEX('%[0-9]%', TXT)
FROM #temp
) d
) t
DROP TABLE #temp

Answer 2

Here's a way without a function....
declare #table table (c varchar(256))
insert into #table
values
('40M'),
('30'),
('5NR'),
('3(-4_')
select
replace(LEFT(SUBSTRING(replace(replace(replace(replace(replace(c,'(',''),')',''),'-',''),' ',''),',',''), PATINDEX('%[0-9.-]%', replace(replace(replace(replace(replace(c,'(',''),')',''),'-',''),' ',''),',','')), 8000),
PATINDEX('%[^0-9.-]%', SUBSTRING(replace(replace(replace(replace(replace(c,'(',''),')',''),'-',''),' ',''),',',''), PATINDEX('%[0-9.-]%', replace(replace(replace(replace(replace(c,'(',''),')',''),'-',''),' ',''),',','')), 8000) + 'X') -1),'.','')
from #table

Answer 3

You go with the PATINDEX function and search for a character that is not a digit. If such an index exists, then grab everything to the left of it. Something like that:
SELECT LEFT(your_field_name, PATINDEX("%[^0-9]%", your_field_name) - 1)
FROM your_table_name
UPDATE
Well, you need to take care of any edge cases. E.g. if there isn't a non-digit data the function will return 0, thus the calculation yields -1, which, indeed, is an invalid length.
I would suggest you to leverage a Common Table Expression to calculate the index of the non-digit data and then construct an IIF expression to select the correct char data. E.g.
WITH cte AS
(
SELECT *, PATINDEX("%[^0-9]%", your_field_name) AS NumLength
FROM your_table_name
)
SELECT any_other_field, IIF(NumLength = 0,
your_field_name,
LEFT(your_field_name, PATINDEX("%[^0-9]%", your_field_name) - 1)
)
FROM cte