Renaming columns - sql, PL-SQL Programming

Assignment Help:

Renaming Columns - SQL

SQL has no direct counterpart of RENAME. To derive the table on the right in Figure 4.4 from the table on the left, Tutorial D has IS_CALLED RENAME ( StudentId AS Sid ).

1010_Renaming Columns - SQL.png

                                                    Figure: Tables differing only in a column name

It shows how the same effect can be achieved in SQL. Note that the SELECT clause has to include all the columns that are not subject to renaming, as well as those that are.

Example: Renaming a column

SELECT StudentId AS Sid, Name

FROM IS_CALLED

Explanation

  • Each element of a SELECT clause is an expression of arbitrary complexity that can reference one or more columns of the SELECT clause's input table. Note that the expression is not required to reference any columns: it might be just a literal, for example.
  • If the expression consists of just a column reference, then the name of the referenced column is the name of the corresponding column in the result.
  • If the expression is followed by the key word AS, then the resulting column has the column name given after that key word.

SQL allows the result to have two or more columns of the same name. For example, if we replace Sid by Name in Example, we still have a valid SQL SELECT expression.


Related Discussions:- Renaming columns - sql

Functions - syntax, Functions The function is a subprogram which can ta...

Functions The function is a subprogram which can take parameters and be invoked. Normally, you can use a function to calculate a value. The function has 2 sections: the specifi

Like operator-comparison operators, LIKE Operator You use the LIKE opera...

LIKE Operator You use the LIKE operator to compare the character value to a pattern. The Case is significant. LIKE returns the Boolean value TRUE when the character patterns mat

Object types and collections - performance of application, Use Object Types...

Use Object Types and Collections The Collection types and object types increase your efficiency by allowing for the realistic data modeling. The Complex real-world entities an

Joining in sql, Joining in SQL Joining IS_CALLED and IS_ENROLLED_ON in...

Joining in SQL Joining IS_CALLED and IS_ENROLLED_ON in SQL SELECT * FROM IS_CALLED NATURAL JOIN IS_ENROLLED_ON This is an example of an SQL table expression. I have been

Calling constructors in pl sql, Calling Constructors: The Calls to a c...

Calling Constructors: The Calls to a constructor are allowed wherever the function calls are allowed. Similarly to the functions, a constructor is called as a section of an ex

Parameter and keyword description - insert statement, Parameter and Keyword...

Parameter and Keyword Description:   table_reference: This identifies a table or view which should be available when you execute the INSERT statement, and for that you sho

Close statement in pl sql, CLOSE Statement The CLOSE statement allows ...

CLOSE Statement The CLOSE statement allows the resources held by a cursor variable or open cursor to be reused. No more rows can be fetched from the cursor variable or closed

Updating tables in sql, Updating Tables in SQL The topic of updating b...

Updating Tables in SQL The topic of updating by describing the assignment operator, ":=" in Tutorial D. SQL uses a different syntax for assignment, using the key word SET and

Initializing and referencing collections, Initializing and Referencing Coll...

Initializing and Referencing Collections Until you initialize a collection, a nested table or varray is automatically null (i.e. the collection itself is null, not its elements)

An active database in pl-sql, Consider the following set of database tables...

Consider the following set of database tables (same tables from Assignment 6-1). Please take note of foreign keys (most of them carry the same names as the corresponding primary ke

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