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Chapter 7

Advanced SQL

Database Systems:Design, Implementation, and Management,

Sixth Edition, Rob and Coronel

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In this chapter, you will learn:

About the relational set operators UNION,

UNION ALL, INTERSECT, and MINUS

How to use the advanced SQL JOIN operatorsyntax

About the different types of subqueries and

correlated queries

How to use SQL functions to manipulate dates,

strings, and other data

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UNION Query Result

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UNION ALL Query Result

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INTERSECT Query Result

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MINUS Query Results

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INTERSECT Alternative

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MINUS Alternative

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SQL Join Expression Styles

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NATURAL JOIN Result

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JOIN USING Result

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JOIN ON Result

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Outer Joins

Returns not only rows matching join condition

but also rows with unmatched values

Three types:

Left

Right

Full

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LEFT JOIN Result

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RIGHT JOIN Result

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FULL JOIN Result

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SELECT Subquery Examples

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WHERE Subquery Examples

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IN Subquery Example

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HAVING Subquery Example

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Multirow Subquery Operator Example

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FROM Subquery Example

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Inline Subquery Example

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Correlated Subquery Examples

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EXISTS Correlated Subquery Examples

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Selected MS Access/SQL Server

Date/Time Functions

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Selected Oracle Date/Time Functions

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Selected Oracle Date/Time Functions

(continued

)

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Selected Oracle Numeric Functions

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Selected Oracle String Functions

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Selected Oracle Conversion Functions

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Selected Oracle Conversion Functions

(continued)

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Oracle Sequence

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Oracle Sequence Examples

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The PRODMASTER

and PRODSALES Tables

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The Oracle UPDATE Error Message

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Creating an Updatable View in Oracle

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PRODMASTER Table Update,

Using an Updatable View

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Anonymous PL/SQL Block Examples

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SHOW ERRORS

Can help diagnose errors found in PL/SQL

blocks

Yields additional debugging information

whenever an error is generated after an

PL/SQL block is created or executed

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Anonymous PL/SQL Block

with Variables and Loops

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PL/SQL Basic Data Types

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The PRODUCT Table

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Creating the

TRG_PRODUCT_REORDER Trigger

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Verifying the TRG_PRODUCT_REORDER

Trigger Execution

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The P_REORDER Value Mismatch After

Update of the P_MIN Attribute

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Stored Procedures: Advantages

Substantially reduce network traffic and

increase performance

No transmission of individual SQL statementsover network

Help reduce code duplication by means of

code isolation and code sharing Minimize chance of errors and cost of

application development and maintenance

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Creating the PRC_PROD_DISCOUNT

Stored Procedure

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Results of the PRC_PROD_DISCOUNT

Stored Procedure

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The PRC_CUS_ADD Stored Procedure

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The PRC_INV_ADD and

PRC_LINE_ADD Stored Procedures

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Testing the PRC_INV_ADD and

PRC_LINE_ADD Procedures

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Cursor Processing Commands

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Cursor Attributes

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SQL and Procedural Languages:

Key Differences Run-time mismatch:

SQL executed one instruction at a time

Host language typically runs at the client sidein its own memory space

Processing mismatch:

Host language processes one data element at

a time

Data type mismatch:

Data types may not match

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Embedded SQL Framework

A standard syntax to identify embedded SQL

code within host language

A standard syntax to identify host variables

A communication area used to exchange

status and error information between SQL

and the host language

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SQL Status and Error Reporting Variables

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Static SQL

Embedded SQL in which the programmer

used predefined SQL statements and

parameters

End users of programs are limited to actions

that were specified in application programs

SQL statements will not change whileapplication is running

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Dynamic SQL

SQL statement is not known in advance, but

instead is generated at run time

Program can generate SQL statements at run

time that are required to respond to ad hocqueries

Attribute list and the condition are not known

until the end user specifies them

Tends to be much slower than static SQL

Requires more computer resources

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Summary

SQL provides relational set operators to

combine output of two queries to generate new

relation

Operations that join tables can be classified asinner joins and outer joins

Subqueries and correlated queries are used

when it is necessary to process data based on

other processed data

SQL functions are used to extract or transform

data

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Summary (continued)

Oracle sequences may be used to generate

values to be assigned to a record

PL/SQL may be used to create triggers,

stored procedures, and PL/SQL functions If SQL statements are designed to return

more than one value inside the PL/SQL code,

a cursor is needed

Embedded SQL refers to the use of SQL

statements within an application

programming language