SQL Server Quotations and Datatypes
Using Literal Values
The following table indicates whether quotes are needed for each of the SQL Server datatypes:
| Datatype | Quotes needed for literal values |
| Binary | No |
| Bit | No |
| Char(n) | Yes |
| Datetime | Yes |
| Decimal(p[,s]) | No |
| Float(n) | No |
| Image | No |
| Int | No |
| Money | No |
| Nchar | Yes |
| Ntext | Yes |
| Numeric | No |
| Nvarchar | Yes |
| Real | No |
| Smalldatetime | Yes |
| Smallint | No |
| Smallmoney | No |
| Text | Yes |
| Timestamp | No |
| Tinyint | No |
| Uniqueidentifier | Yes if string, No if hexadecimal |
| Varbinary | No |
| Varchar(n) | No |
Single versus double quotations
Microsoft recommends using single quotation marks for literal values, but you should know that you can, if desired, use double quotes by issuing the following Transact-SQL statement first:
SET QUOTED_IDENTIFIER OFF
Once you issue this Transact-SQL statement, you can use double quotes for the entire lifetime of your database connection. You do not have to issue this Transact-SQL statement before every statement that uses double quotes.