Union and or - sql, PL-SQL Programming

Assignment Help:

UNION and OR - SQL

SQL supports UNION explicitly but differently from the way it supports JOIN explicitly. As we have seen, JOIN is used exclusively within the FROM clause, such that IS_CALLED NATURAL JOIN IS_ENROLLED_ON, for example, can be an element of that clause but cannot stand alone as a table expression. Instead, UNION always connects table expressions that can stand alone, these being:

  1. SELECT expressions
  2. TABLE tn, which is equivalent to SELECT * FROM tn, where tn is a table name
  3. VALUES expressions
  4. Invocations of UNION, INTERSECT and EXCEPT

Related Discussions:- Union and or - sql

Using set transaction, Using SET TRANSACTION You use the SET TRANSACTI...

Using SET TRANSACTION You use the SET TRANSACTION statement to begin the read-only or read-write transaction, start an isolation level, or assign your present transaction to a

Example of groupby operator - sql, Example of GROUPBY Operator Example...

Example of GROUPBY Operator Example: How many students sat each exam, using GROUP BY, NATURAL LEFT JOIN, and COALESCE SELECT CourseId, COALESCE (n, 0) AS n FROM COURS

Using delete - collection method, Using DELETE This process has three ...

Using DELETE This process has three forms. The DELETE removes all elements from the collection. DELETE(n) removes the nth element from the nested table. When n is null, then D

I need sql - wp sql expert, I need SQL , WP SQL Expert Project Descripti...

I need SQL , WP SQL Expert Project Description: Expert required to modify WP SQL query. Skills required are MySQL, SQL, PHP, Wordpress

Advantages of exceptions, Advantages of Exceptions Using the exception...

Advantages of Exceptions Using the exceptions for the error handling has many benefits. Without an exception handling, every time you issue a command, you should ensure for th

Delete command - sql, DELETE Command - SQL Loosely speaking, DELETE re...

DELETE Command - SQL Loosely speaking, DELETE removes some existing rows from its target table. Suppose the university decides that course C3 is to be withdrawn. Example shows

Multiple assignment - sql, Multiple Assignment- SQL SQL supports mult...

Multiple Assignment- SQL SQL supports multiple assignment to local variables and also applies multiple assignment semantics in SET clauses of UPDATE statements, but does not

Long and long raw in pl/sql, LONG and LONG RAW You use the LONG datatyp...

LONG and LONG RAW You use the LONG datatype to store the variable-length character strings. The LONG datatype is such as the VARCHAR2 datatype, except that the maximum length o

Understanding nested tables, Understanding Nested Tables Within the data...

Understanding Nested Tables Within the database, the nested tables can be considered as one-column database tables. The Oracle stores the rows of a nested table in no specific o

Parameter and keyword description - select into statement, Parameter and Ke...

Parameter and Keyword Description: select_item: This select_item is a value returned by the SELECT statement, and then assigned to the equivalent variable or field in the

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