Sybase 12.4.2 用户手册

CHAPTER 6    Using Procedures and Batches

You can take advantage of default values of stored procedure parameters with 
either of two forms of the CALL statement.

If the optional parameters are at the end of the argument list in the CREATE 
PROCEDURE statement, they may be omitted from the CALL statement. As 
an example, consider a procedure with three INOUT parameters:

CREATE PROCEDURE SampleProc( INOUT var1 INT 

DEFAULT 1,

INOUT var2 int DEFAULT 2,

INOUT var3 int DEFAULT 3 )

...

We assume that the calling environment has set up three variables to hold the 
values passed to the procedure:

CREATE VARIABLE V1 INT;

CREATE VARIABLE V2 INT;

CREATE VARIABLE V3 INT;

The procedure 

SampleProc

 may be called supplying only the first parameter as 

follows:

CALL SampleProc( V1 )

in which case the default values are used for var2 and var3.

A more flexible method of calling procedures with optional arguments is to 
pass the parameters by name. The 

SampleProc

 procedure may be called as 

follows:

CALL SampleProc( var1 = V1, var3 = V3 )

or as follows:

CALL SampleProc( var3 = V3, var1 = V1 )

User-defined functions are not invoked with the CALL statement, but are used 
in the same manner that built-in functions are. For example, the following 
statement uses the 

fullname

 function defined in “Creating user-defined 

functions” to retrieve the names of all employees:

SELECT fullname(emp_fname, emp_lname) AS Name

FROM employee