Example of coalesce operator - sql, PL-SQL Programming

Assignment Help:

Example of COALESCE operator

Example: Give the total of marks for each exam (simplified solution)

SELECT CourseId,

COALESCE ((SELECT SUM (Mark)

FROM EXAM_MARK AS EM

WHERE EM.CourseId = C.CourseId ),

0) AS TotalMark

FROM COURSE AS C

Explanation

The first operand to the invocation of COALESCE is a scalar subquery similar to Aggregate Operators. Recall the need to enclose the SELECT expression in parentheses, without which it would denote a table rather than a number.

Related Discussions:- Example of coalesce operator - sql

Open-for statement, OPEN-FOR Statement The OPEN-FOR statements execute ...

OPEN-FOR Statement The OPEN-FOR statements execute the multi-row query related with a cursor variable. It also allocates the resources used by the Oracle to process the query a

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

Entering and exiting - autonomous transaction, Entering and Exiting If...

Entering and Exiting If you enter the executable part of an autonomous routine, the major transaction suspends. When you exit the routine, the major transaction resumes. To ex

Type versus representation confusion in sql, Type versus Representation Con...

Type versus Representation Confusion in SQL This describes how a value might have two or more distinct representations. For example, user-defined type POINT might have a decla

Rephrase conditional control statements, Rephrase Conditional Control State...

Rephrase Conditional Control Statements When computing a logical expression, the PL/SQL uses short-circuit evaluation. That is, the PL/SQL stops evaluating the expression as s

Solve the business problems using sql, Use the MASCOT tables CREDITRS, PORD...

Use the MASCOT tables CREDITRS, PORDS and PAYMENTS to write SQL queries to solve the following business problems. These tables / data are available to you via the USQ Oracle server

Example of null operator - nino rule, Example of Null operator - NiNo Rule ...

Example of Null operator - NiNo Rule If we wanted to make HIGHER_OF adhere to "NULL in, NULL out"-let's call it the NiNo rule-we would have to write something like what is sho

Example of delete - sql, Example of DELETE - SQL As with UPDATE, a FOR...

Example of DELETE - SQL As with UPDATE, a FOR PORTION OF clause can be specified if the target table has a defined period name, as illustrated in Example. Example: Deleting

Set operators - sql operators, Set Operators The Set operators combine...

Set Operators The Set operators combine the results of the two queries into one result. The INTERSECT returns all the distinct rows selected by both queries. The MINUS returns

Advantages of pl/sql, Advantages of PL/SQL The PL/SQL is a high-perform...

Advantages of PL/SQL The PL/SQL is a high-performance transaction processing, completely portable language that offers the following advantages as shown: 1) Support for SQL

Write Your Message!

Name

Email id

Message

Verfication Code

User Account

All Pages