Week 2b Where

8/9/2019 Week 2b Where

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Producing Readable Outputwith iSQL*Plus


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Objectives

After completing this lesson, you should be abke to do the following

Producing queries that require a substitutuin variableCustomize the iSQL*Plus environment

Produce more readable outputCreate and Execute script file


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Subtitution Variables

SAL = ?D EPTNO =?..,JOB=?

I want to querydifferent values.


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U sing iSQL*Plus, you can create reports that prompt the user to supply their ownvalues to restrict the range of data returned by using substitution variables.

You can embed substitution variables in a command file or in a single SQL statement. A varaible can be thought as a container in which the values are temporarily stored.When the statement is run, the value is substituded.

U se iSQL*Plus substitution variables to :

Store values temporarilySingle ampersand &D ouble ampersand &&D EFINE command

Pass variable values between SQL statements.Dynamically alter headers and footers


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U sing the & substitution variable

U se a variable prefixed with an ampersand (&) to prompt the user for a value

SELECT empno,ename,sal,deptnoFROM empWHERE empno= &employee number;

Variable as a number

Number Values with Substitution Variables


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SELECT empno,ename,sal,deptnoFROM empWHERE job= '& job ';

Character and D ate Values with Substitution Variables

Variable as a Character or D ate


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Specifying Column Names, Expressions, and Text

U se substitution variables to supplement the

following :

WHERE conditionsORDER BY clauses

Column ExpressionsTable namesEntire SELECT statements

Not only can you use the substitution variables in the WHERE clause of an SQLStatement, but these variables can also be used to substitute for column names,Expressions, or text.


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SELECT empno ,&COLU MN_NAMEFROM empWHERE &COND ITION ;


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SELECT empno,ename,job,&COL U MN_NAMEFROM empWHERE &COND ITIONOR D ER BY &OR D ER_COL U MN;


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SELECT empno,ename,job,&COL U MN_NAMEFROM empWHERE &COND ITIONOR D ER BY &OR D ER_COL U MN;


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Defining Substitution Variables

You can predefine variables using the iSQL*Plus D EFINE command.

D EFINE variable = value creates a user variable with the CHAR data type

If you need to predefine a variable that includes spaces, you must enclosethe value within single quotation marks when using the D EFINE command.

A D efine variable is available for the session.

Command Description

D EFINE variable=value Create a user variable with the CHAR data andassigns a value to it.

D EFINE variable D isplays the variable, its value,and its data type

D EFINE D isplays all user variables with their values,and datatypes


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D EFINE SALARY=800

SELECT ENAME,SAL FROM EMP WHERE SAL= &SALARY


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UN DEFI N E command

Variables are defined until you either :

Issue the U ND EFINE D command on a variable,

Exit iSQL*Plus


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U sing the && Substitution Variable

U se the double-ampersand (&&) if you want to reuse the variable value withoutprompting the user each time.

SELECT empno, ename ,&&COLU MN_NAME FROM emp order by &COLU MN_NAME;


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U sing the VERIFY Command

SET VERIFY O NSELECT empno,ename,sal,deptno

FROM empWHERE empno=&employee_number;

This is displayed if VERIFY is ON


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U sing the VERIFY Command

SET VERIFY OFFSELECT empno,ename,sal,deptno

FROM empWHERE empno=&employee_number;


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iSQL*Plus Format Commands

COL UMN

TTITLE

BTITLE

BREAK


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The COL U MN command

OPTION

S DESCRIPTION

SCLEAR Clears any column formatsHEAD ING Sets the column headingFORMAT Changes the display of the column dataNOPRINT Hide the columnsNU LL Specifies text to be displayed for null valuesPRINT Shows the columns


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COLU MN FORMAT MO D EL

ELEMENT D ESCRIPTION EXAMPLE

9 Single Zero-suppression digit 999999

0 Enforces leading zero 099999

$ Floating dollar sign $99999

L Local currency L99999

. Position of decimal point 9999.99

, Thousand seperator 9,9999


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U sing BREAK command

U se the BREAK command to suppress duplicates.

Break on deptno ;

Select * from emp order by deptno ;

CLEAR BREAK


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HEAD ERS AN D FOOTERS

D ISPLAY HEA D ERS AN D FOOTERS

TITLE O N BTITLE O NTTITLE OFF BTITLE OFF

Set the Report Header

TTITLE EM PLOYEE LIST

Set the Report Footer

BTITLE CO N FIDE N TAL


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TTITLE 'E M PLOYEES LIST'BTITLE 'CO N FIDE N TAL'SELECT * FRO M EM P;


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4 -Write a script to display the ename, job, and department names for every employee ina given location. Search condition should allow for case-intensive searches of thedepartment location.

5-Modiyf the code of task 4 to create a report containing the department name,employee name, hiredate, salary and, and ANN U AL SALARY.

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Week 2b Where