Empty Strings (Level 2)
|SQL Server 6.x||SQL Server 2000|
|An empty string could be interpreted as either a NULL or a single blank character.||Interpretation of an empty string is controlled by the compatibility level, which is set with the sp_dbcmptlevel system stored procedure. If the compatibility level is 65 or lower, SQL Server interprets empty strings as single spaces. If the compatibility level is 70 or 80, SQL Server interprets empty strings as empty strings. For more information, see sp_dbcmptlevel.
Expect differences in interpretation of empty strings compared to earlier versions of SQL Server. Transact-SQL functions and statements affected by the setting of sp_dbcmptlevel include CHARINDEX, DATALENGTH, LEFT, LTRIM, PATINDEX, REPLICATE, RIGHT, RTRIM, SPACE, SUBSTRING, and UPDATETEXT.