SQL Escape ' '

问题:

I am trying to run a query in SQL 2008 by doing:

@query varchar(max)

SET @query = 'SELECT * FROM Table WHERE [Name] = ' 'Karl' ' '

EXEC(@query)

The problem is that for some reason the apostrophes around 'Karl' don't get escaped, i.e. the query executes as ...WHERE [Name] = Karl and fails.

Anyone have a suggestion?

Thanks

Karl

回答1:

There are several ways that you can escape character data in SQL Server, some people even advocate the use of the QUOTENAME() functions.

If you really want to develop of solid understanding of this subject area then may I recommend that you take a look at what experienced SQL Server Developers consider to be essential reading with regard to the different methods you can use to incorporate Dynamic T-SQL into your coding.

The Curse and Blessings of Dynamic SQL

回答2:

Try:

DECLARE @query varchar(max)

SET @query = 'SELECT * FROM Table WHERE [Name] = ''Karl'''

PRINT 'when in doubt, print the query out: '+ISNULL(@query,'')
EXEC(@query)

To have a single quote appear, you need to have two adjacent single quotes. You escape a single quote with a single quote, for example:

PRINT ''''     --will print a one single quote
PRINT ''''''   --will print two single quotes
PRINT 'can''t' --will print can't

回答3:

This works on my machine from SQL Server Management Studio:

@query varchar(max)

SET @query = 'SELECT * FROM Table WHERE [Name] = ''''''Karl'''''''

EXEC(@query)

回答4:

do like this SET @query = 'SELECT * FROM Table WHERE [Name] = ''''Karl'''''

回答5:

A double single ('') quote will act like a single single quote when inside a string literal.

Have you tried using a variable?

declare @karl_name varchar(10);
set @karl_name = '''Karl''';

SELECT * FROM Table WHERE [Name] = @karl_name

回答6:

This works:

create table #demo([Name] varchar(max))
insert into #demo([Name]) values('''Karl''')
insert into #demo([Name]) values('Karl')
declare @query varchar(max)
set @query = 'SELECT * FROM #demo WHERE [Name] = ''''''Karl'''''''
EXEC(@query)

Output:

'Karl'

But if 'Karl' is variable text, it's highly recommended to use something like this instead:

declare @query nvarchar(max)
declare @param varchar(max)
set @param = N'''Karl'''
set @query = N'SELECT * FROM #demo WHERE [Name] = @param'
exec sp_executesql @query, N'@param varchar(max)', @param

回答7:

Simply escape the apostrophes by using the escaping bar \ like this 'SELECT * FROM Table WHERE [Name] = ' \'Karl\' ' '

Hope it helps