Introduction to Oracle9i – SQL

by Frank4DD, @2004

Writing Basic SQL Select Statements (Module 2)

  1. List the capabilities of SQL SELECT statements

    Projection - select specific columns from all rows

    Selection - query specific rows from all columns

    Join Operations - Combine data between 2 different tables

  1. Execute a basic SELECT statement

    syntax:

    SELECT *|{[DISTINCT] column|expression [alias],...} FROM table;

    example:

    SELECT * FROM employees;

    explanation:

    SELECT identifies what columns, FROM identifies which table.

  1. Differentiate between SQL statements and iSQL*Plus commands

    SQL

    iSQL*Plus

    non-procedural language (statements)

    is an Oracle proprietary environment (commands)

    keywords can't be abbreviated

    keywords can be abbreviated

    statements manipulate data and table definitions in the database

    commands do not allow manipulation of values in the database


    Runs in a browser
Test Quiz for Writing Basic SQL Select Statements (Module 2)

  1. Indicate the terms used for column and the row capabilities of select statements from the list below.
    (There are two correct answers.)

    2. X

    Projection returns the desired columns in a query.


    Selection returns the desired columns in a query.

    X

    Selection returns the desired rows in a query.


    Restriction eliminates unneeded columns in a query


    Restriction eliminates unneeded rows in a query.


    Projection returns the desired rows in a query.

  1. Choose the correct answer regarding the DESCRIBE syntax:
    (There is only one correct answer.)

    2. X

    It displays the structure of a database object (like a table), but is not a SQL command.


    It is a SQL statement that returns the structure of a table. (WRONG!)


    It displays the format options that have been set for SQLPLUS or iSQLPLUS.


    It displays the execution plan for a SQL statement.

  1. Which queries would return a result of 50?
    (There are two correct answers.)


    		2.

    Select (100*(2+50)/5) from dual;

    X

    Select (100*2+50)/5 from dual;

    X

    Select ((100 *2)+50)/5 from dual;


    Select (100)*2+(50/5) from dual;


    Select 100*2 +50/5 from dual;

  1. For a column alias to contain a space or retain case, it must:
    (Choose the best answer)


    2. Be enclosed within single quotation marks (WRONG!)


    Be enclosed within curly braces


    Be enclosed within parenthesis

    X

    Be enclosed within double quotation marks


    Be preceded by the ampersand symbol

  1. Which of the following statements are true about iSQL*PLUS?
    (There are two correct answers.)


    2. iSQL*PLUS permits its own commands as well as SQL commands to be abbreviated


    iSQL*PLUS must be installed on the database server as well as each client machine.

    X

    iSQL*PLUS runs on an Internet browser, but can be centrally loaded through a URL.


    iSQL*PLUS is an ANSI standard product for accessing databases.

    X

    iSQL*PLUS is an Oracle tool with its own non-SQL commands.