Question

I’m trying find the best way to remove nonnumerical data from a varchar in SQL e.g.

'[phone]' to '0820000000' or '[phone]' to '0820000000' 

The difficulty is i’m not always sure what number formats are coming in, as shown above, so I’d like like everything that is not a number removed essentially.

Update:
From what you guys have said this is a little spike done:

declare @Num varchar(20)  set @Num = ' + (82) 468 6152 '  --strip nonnumrical data out of @num  print @Num  set @Num = replace(@Num, ' ', '') set @Num = replace(@Num, '+', '') set @Num = replace(@Num, '-', '') set @Num = replace(@Num, '(', '') set @Num = replace(@Num, ')', '')  print @Num 

Couldn’t get the replace [^0-9] expression right though.

Answer 1

If you’re using SQL Server 2005 or newer then your best option is to create a user-defined CLR function and use a regular expression to remove all non-numeric characters.

If you don’t want to use a CLR function then you could create a standard user-defined function. This will do the job although it won’t be as efficient:

CREATE FUNCTION dbo.RemoveNonNumerics(@in VARCHAR(255)) RETURNS VARCHAR(255) AS BEGIN     DECLARE @out VARCHAR(255)      IF (@in IS NOT NULL)     BEGIN         SET @out = ''          WHILE (@in <> '')         BEGIN             IF (@in LIKE '[0-9]%')                 SET @out = @out + SUBSTRING(@in, 1, 1)              SET @in = SUBSTRING(@in, 2, LEN(@in) - 1)         END     END      RETURN(@out) END 

And then select from your table like so:

SELECT dbo.RemoveNonNumerics(your_column) AS your_tidy_column FROM your_table