Effects of null for multiple assignments - sql, PL-SQL Programming

Assignment Help:

Effects of NULL for Multiple Assignments - SQL

If the row expression given as the source for a multiple assignment evaluates to NULL, then NULL is assigned to each target. If a SELECT ... INTO statement results in an empty table, then the target variables are not updated and a completion condition is given to indicate that. This is not exactly an "effect of NULL", of course, but I mention it here because of the contrast with a row subquery, which delivers a single row with NULL for each field when its table expression evaluates to an empty table. This observation might influence the choice between SET and SELECT ... INTO.


Related Discussions:- Effects of null for multiple assignments - sql

Parameter and keyword description - procedures, Parameter and Keyword Descr...

Parameter and Keyword Description: procedure_name The user-defined procedure is declared by this construct. parameter_name: This identifies the formal parameter t

Second step at defining type sid in sql, Second Step at defining type SID i...

Second Step at defining type SID in SQL CREATE TYPE SID AS VARCHAR(5) ; Explanation: TYPE SID announces that a type named SID is being defined to the system.

Count operator in sql, Count Operator in SQL Example: Counting the stu...

Count Operator in SQL Example: Counting the students who have scored more than 50 in some exam (SELECT COUNT (*) FROM (SELECT DISTINCT StudentId FROM EXAM_MARK WHE

Other monadic - sql, Other monadic - SQL In 2VL there are just 4 (2 2 ...

Other monadic - SQL In 2VL there are just 4 (2 2 ) monadic operators, of which negation is really the only "useful" one. When a third truth value is introduced we have 27 (3 3

Use triggers to maintain referential integrity, At times, Brewbean's has ch...

At times, Brewbean's has changed the id number for existing products. In the past, they have had to add a new product row with the new id to the BB_PRODUCT table, modify all the co

Updating a variable, Updating a Variable Assignment of an attribute va...

Updating a Variable Assignment of an attribute value in a variable of a structured type Synatx: SET SN.C = 'S2'; As in Example the entire statement is equivalent to a

Dynamic sql - pl sql, Dynamic SQL: The Most PL/SQL programs do a predi...

Dynamic SQL: The Most PL/SQL programs do a predictable, specific job. For illustration, a stored procedure may accept an employee number and salary increase, and then update t

Rewrite rules - tautology, Equivalences & Rewrite Rules: If notice tha...

Equivalences & Rewrite Rules: If notice that as well as allowing us to prove trivial theorems, and tautologies enable us to establish that certain sentences are saying the sam

Package - pl/sql programming, What Is a Package? The package is a sch...

What Is a Package? The package is a schema object that group logically related PL/SQL items, types, and subprograms. The Packages usually have 2 parts, a specification & a bo

Using commit, Using COMMIT The COMMIT statements end the present trans...

Using COMMIT The COMMIT statements end the present transaction and make permanent any changes made during that transaction. Till you commit the changes, other users cannot acc

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd