SQL Server 2008 query to find rows containing non-alphanumeric characters in a column

Question

I was actually asked this myself a few weeks ago, whereas I know exactly how to do this with a SP or UDF but I was wondering if there was a quick and easy way of doing this

Answer 1

Sql server has very limited Regex support. You can use PATINDEX with something like this

PATINDEX('%[a-zA-Z0-9]%',Col)

Have a look at PATINDEX (Transact-SQL)

and Pattern Matching in Search Conditions

Answer 2

I found this page with quite a neat solution. What makes it great is that you get an indication of what the character is and where it is. Then it gives a super simple way to fix it (which can be combined and built into a piece of driver code to scale up it's application).

DECLARE @tablename VARCHAR(1000) ='Schema.Table'
DECLARE @columnname VARCHAR(100)='ColumnName'
DECLARE @counter INT = 0
DECLARE @sql VARCHAR(MAX)

WHILE @counter <=255
BEGIN

SET @sql=

'SELECT TOP 10 '+@columnname+','+CAST(@counter AS VARCHAR(3))+' as CharacterSet, CHARINDEX(CHAR('+CAST(@counter AS VARCHAR(3))+'),'+@columnname+') as LocationOfChar
FROM '+@tablename+'
WHERE CHARINDEX(CHAR('+CAST(@counter AS VARCHAR(3))+'),'+@columnname+') <> 0'

PRINT (@sql)
EXEC (@sql)
SET @counter = @counter + 1
END

and then...

UPDATE Schema.Table
SET ColumnName= REPLACE(Columnname,CHAR(13),'')

Credit to Ayman El-Ghazali.

Answer 3

Won't this do it?

SELECT * FROM TABLE
WHERE COLUMN_NAME LIKE '%[^a-zA-Z0-9]%'

Setup

use tempdb
create table mytable ( mycol varchar(40) NULL)

insert into mytable VALUES ('abcd')
insert into mytable VALUES ('ABCD')
insert into mytable VALUES ('1234')
insert into mytable VALUES ('efg%^&hji')
insert into mytable VALUES (NULL)
insert into mytable VALUES ('')
insert into mytable VALUES ('apostrophe '' in a sentence') 

SELECT * FROM mytable
WHERE mycol LIKE '%[^a-zA-Z0-9]%'

drop table mytable 

Results

mycol
----------------------------------------
efg%^&hji
apostrophe ' in a sentence