Sybase 12.4.2 Calling external libraries from procedures, Using Select statements in batches, 268

Calling external libraries from procedures

Using SELECT statements in batches

You can include one or more SELECT statements in a batch. Multiple SELECT statements are allowed by Interactive SQL only if they return the same number of columns and each column has the same data type.

The following is a valid batch:

IF EXISTS(SELECT *

FROM systable

WHERE table_name=’employee’ )

THEN

SELECTemp_lname AS LastName, emp_fname AS FirstName

FROM employee; SELECT lname, fname FROM customer;

SELECT last_name, first_name FROM contact;

END IF

The alias for the result set is required only in the first SELECT statement, as the server uses the first SELECT statement in the batch to describe the result set.

A RESUME statement is required following each query to retrieve the next result set.

The following is not a valid batch, as the two queries return different result sets:

IF EXISTS( SELECT * FROM systable WHERE table_name=’employee’ )

THEN

SELECTemp_lname AS LastName, emp_fname AS FirstName

FROM employee;

SELECT id, lname, fname FROM customer;

END IF

Calling external libraries from procedures

You can call a function in an external Dynamic Link Library (DLL) from a stored procedure or user-defined functions under an operating system that supports DLLs. You cannot use external functions on UNIX.

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