Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Appendix A: System Functions
NULLIF
The NULLIF function compares two expressions and returns a NULL value. The syntax is as follows:
NULLIF(, )
PARSENAME
The PARSENAME function returns the specified part of an object name. The syntax is as follows:
PARSENAME(‘’, )
The object_name parameter specifies the object name from the part that is to be retrieved. The
object_piece parameter specifies the part of the object to return. The object_piece parameter takes
one of these possible values:
❑ 1 — Object name
❑ 2 — Owner name
❑ 3 — Database name
❑ 4 — Server name
PERMISSIONS
The PERMISSIONS function returns a value containing a bitmap, which indicates the statement, object, or
column permissions for the current user. The syntax is as follows:
PERMISSIONS([ [, ‘’]])
The object_id parameter specifies the ID of an object. The optional column parameter specifies the
name of the column for which permission information is being returned.
@@ROWCOUNT
Returns the number of rows affected by the last statement.
One of the most used globals, my most common use for this one is to check for non–run-time errors — that
is, items that are logically errors to your program but that SQL Server isn’t going to see any problem with.
An example is a situation where you are performing an update based on a condition, but you find that it
affects zero rows. Odds are that, if your client submitted a modification for a particular row, then it was
expecting that row to match the criteria given — zero rows affected is indicative of something being wrong.
However, if you test this system function on any statement that does not return rows, then you will also
return a value of 0.
ROWCOUNT_BIG
644
The ROWCOUNT_BIG function is very similar to @@ROWCOUNT in that it returns the number of rows from
the last statement. However, the value returned is of a data type of bigint. The syntax is as follows:
ROWCOUNT_BIG()