- •Preface
- •Introduction
- •Lesson Objectives
- •Lesson Agenda
- •Course Objectives
- •Course Agenda
- •Appendixes Used in the Course
- •Lesson Agenda
- •Oracle Database 11g: Focus Areas
- •Oracle Database 11g
- •Oracle Fusion Middleware
- •Oracle Enterprise Manager Grid Control 10g
- •Oracle BI Publisher
- •Lesson Agenda
- •Relational and Object Relational Database Management Systems
- •Data Storage on Different Media
- •Relational Database Concept
- •Definition of a Relational Database
- •Data Models
- •Entity Relationship Model
- •Relating Multiple Tables
- •Relational Database Terminology
- •Lesson Agenda
- •Using SQL to Query Your Database
- •SQL Statements
- •Development Environments for SQL
- •Lesson Agenda
- •The Human Resources (HR) Schema
- •Tables Used in the Course
- •Lesson Agenda
- •Oracle Database 11g Documentation
- •Additional Resources
- •Summary
- •Practice I: Overview
- •Objectives
- •Lesson Agenda
- •Capabilities of SQL SELECT Statements
- •Basic SELECT Statement
- •Selecting All Columns
- •Selecting Specific Columns
- •Writing SQL Statements
- •Column Heading Defaults
- •Lesson Agenda
- •Arithmetic Expressions
- •Using Arithmetic Operators
- •Operator Precedence
- •Defining a Null Value
- •Null Values in Arithmetic Expressions
- •Lesson Agenda
- •Defining a Column Alias
- •Using Column Aliases
- •Lesson Agenda
- •Concatenation Operator
- •Literal Character Strings
- •Using Literal Character Strings
- •Alternative Quote (q) Operator
- •Duplicate Rows
- •Lesson Agenda
- •Displaying the Table Structure
- •Using the DESCRIBE Command
- •Quiz
- •Summary
- •Practice 1: Overview
- •Objectives
- •Lesson Agenda
- •Limiting Rows Using a Selection
- •Limiting the Rows That Are Selected
- •Using the WHERE Clause
- •Character Strings and Dates
- •Comparison Operators
- •Using Comparison Operators
- •Range Conditions Using the BETWEEN Operator
- •Membership Condition Using the IN Operator
- •Pattern Matching Using the LIKE Operator
- •Combining Wildcard Characters
- •Using the NULL Conditions
- •Defining Conditions Using the Logical Operators
- •Using the AND Operator
- •Using the OR Operator
- •Using the NOT Operator
- •Lesson Agenda
- •Rules of Precedence
- •Lesson Agenda
- •Using the ORDER BY Clause
- •Sorting
- •Lesson Agenda
- •Substitution Variables
- •Using the Single-Ampersand Substitution Variable
- •Character and Date Values with Substitution Variables
- •Specifying Column Names, Expressions, and Text
- •Using the Double-Ampersand Substitution Variable
- •Lesson Agenda
- •Using the DEFINE Command
- •Using the VERIFY Command
- •Quiz
- •Summary
- •Practice 2: Overview
- •Objectives
- •Lesson Agenda
- •SQL Functions
- •Two Types of SQL Functions
- •Single-Row Functions
- •Lesson Agenda
- •Character Functions
- •Case-Conversion Functions
- •Using Case-Conversion Functions
- •Character-Manipulation Functions
- •Using the Character-Manipulation Functions
- •Lesson Agenda
- •Number Functions
- •Using the ROUND Function
- •Using the TRUNC Function
- •Using the MOD Function
- •Lesson Agenda
- •Working with Dates
- •RR Date Format
- •Using the SYSDATE Function
- •Arithmetic with Dates
- •Using Arithmetic Operators with Dates
- •Lesson Agenda
- •Date-Manipulation Functions
- •Using Date Functions
- •Using ROUND and TRUNC Functions with Dates
- •Quiz
- •Summary
- •Practice 3: Overview
- •Objectives
- •Lesson Agenda
- •Conversion Functions
- •Implicit Data Type Conversion
- •Explicit Data Type Conversion
- •Lesson Agenda
- •Using the TO_CHAR Function with Dates
- •Elements of the Date Format Model
- •Using the TO_CHAR Function with Dates
- •Using the TO_CHAR Function with Numbers
- •Using the TO_NUMBER and TO_DATE Functions
- •Using the TO_CHAR and TO_DATE Function with RR Date Format
- •Lesson Agenda
- •Nesting Functions
- •Lesson Agenda
- •General Functions
- •NVL Function
- •Using the NVL Function
- •Using the NVL2 Function
- •Using the NULLIF Function
- •Using the COALESCE Function
- •Lesson Agenda
- •Conditional Expressions
- •CASE Expression
- •Using the CASE Expression
- •DECODE Function
- •Using the DECODE Function
- •Quiz
- •Summary
- •Practice 4: Overview
- •Objectives
- •Lesson Agenda
- •What Are Group Functions?
- •Types of Group Functions
- •Group Functions: Syntax
- •Using the AVG and SUM Functions
- •Using the MIN and MAX Functions
- •Using the COUNT Function
- •Using the DISTINCT Keyword
- •Group Functions and Null Values
- •Lesson Agenda
- •Creating Groups of Data
- •Creating Groups of Data: GROUP BY Clause Syntax
- •Using the GROUP BY Clause
- •Grouping by More than One Column
- •Using the GROUP BY Clause on Multiple Columns
- •Illegal Queries Using Group Functions
- •Restricting Group Results
- •Restricting Group Results with the HAVING Clause
- •Using the HAVING Clause
- •Lesson Agenda
- •Nesting Group Functions
- •Quiz
- •Summary
- •Practice 5: Overview
- •Objectives
- •Lesson Agenda
- •Types of Joins
- •Joining Tables Using SQL:1999 Syntax
- •Qualifying Ambiguous Column Names
- •Lesson Agenda
- •Creating Natural Joins
- •Retrieving Records with Natural Joins
- •Creating Joins with the USING Clause
- •Joining Column Names
- •Retrieving Records with the USING Clause
- •Using Table Aliases with the USING Clause
- •Creating Joins with the ON Clause
- •Retrieving Records with the ON Clause
- •Creating Three-Way Joins with the ON Clause
- •Applying Additional Conditions to a Join
- •Lesson Agenda
- •Joining a Table to Itself
- •Self-Joins Using the ON Clause
- •Lesson Agenda
- •Nonequijoins
- •Retrieving Records with Nonequijoins
- •Lesson Agenda
- •INNER Versus OUTER Joins
- •LEFT OUTER JOIN
- •RIGHT OUTER JOIN
- •FULL OUTER JOIN
- •Lesson Agenda
- •Cartesian Products
- •Generating a Cartesian Product
- •Creating Cross Joins
- •Quiz
- •Summary
- •Practice 6: Overview
- •Objectives
- •Lesson Agenda
- •Using a Subquery to Solve a Problem
- •Subquery Syntax
- •Using a Subquery
- •Guidelines for Using Subqueries
- •Types of Subqueries
- •Lesson Agenda
- •Single-Row Subqueries
- •Executing Single-Row Subqueries
- •Using Group Functions in a Subquery
- •The HAVING Clause with Subqueries
- •What Is Wrong with This Statement?
- •No Rows Returned by the Inner Query
- •Lesson Agenda
- •Multiple-Row Subqueries
- •Lesson Agenda
- •Null Values in a Subquery
- •Quiz
- •Summary
- •Practice 7: Overview
- •Objectives
- •Lesson Agenda
- •Set Operators
- •Set Operator Guidelines
- •The Oracle Server and Set Operators
- •Lesson Agenda
- •Tables Used in This Lesson
- •Lesson Agenda
- •UNION Operator
- •Using the UNION Operator
- •UNION ALL Operator
- •Using the UNION ALL Operator
- •Lesson Agenda
- •INTERSECT Operator
- •Using the INTERSECT Operator
- •Lesson Agenda
- •MINUS Operator
- •Using the MINUS Operator
- •Lesson Agenda
- •Matching the SELECT Statements
- •Matching the SELECT Statement: Example
- •Lesson Agenda
- •Using the ORDER BY Clause in Set Operations
- •Quiz
- •Summary
- •Practice 8: Overview
Using Table Aliases with the USING Clause
•Do not qualify a column that is used in the USING clause.
•If the same column is used elsewhere in the SQL statement, do not alias it.
SELECT l.city, d.department_name
FROM locations l JOIN departments d
USING (location_id)
WHERE d.location_id = 1400;
Copyright © 2009, Oracle. All rights reserved.
Using Table Aliases with the USING clause |
Academy |
When joining with the USING clause, you cannotOraclequalify a co umn that is used in the USING clause
itself. Furthermore, if that column is used anywhere in the SQL statement, you cannot alias it. For
example, in the query mentioned in the slide, you should not lias the location_id column in the |
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WHERE clause because the column is used in the USING clause. |
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The columns that are referenced in the USING clause should not have a qualifier (table name or |
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alias) anywhere in the SQL statement. For&example, the following statement is valid: |
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SELECT l.city, d.department_name |
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FROM |
locations l JOIN departm nts d USING (location_id) |
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WHERE |
location id = 1400; |
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Because, other colum s hat are commonUsein both the tables, but not used in the USING clause, must |
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be prefixed with a table alias otherwise you get the “column ambiguously defined” error. |
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In the following statement, manager_id is present in both the employees and departments |
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table and if manager_id is not prefixed with a table alias, it gives a “column ambiguously |
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defined” error. |
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The following statement is valid: |
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SELECT |
first_name, |
d.department_name, |
d.manager_id |
FROM |
employees e |
JOIN departments d |
USING (department_id) |
WHERE |
department_id = 50; |
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Oracle Database 11g: SQL Fundamentals I 6 - 14
Creating Joins with the ON Clause
•The join condition for the natural join is basically an equijoin of all columns with the same name.
•Use the ON clause to specify arbitrary conditions or specify columns to join.
•The join condition is separated from other search conditions.
•The ON clause makes code easy to understand.
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Copyright © 2009, Oracle. All rights reserved. |
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Creating Joins with the ON Clause |
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Use the ON clause to specify a join condition. With this, you can sp cify join conditions separate |
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from any search or filter conditions in the WHERE clause. |
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Oracle Database 11g: SQL Fundamentals I 6 - 15
Retrieving Records with the ON Clause
SELECT e.employee_id, e.last_name, e.department_id, d.department_id, d.location_id
employees e JOIN departments d (e.department_id = d.department_id);
…
Copyright © 2009, Oracle. All rights reserved.
Retrieving Records with the ON Clause |
Academy |
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Oracle |
You can also use the ON clause to join columns that have different names. The parenthesis around |
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the joined columns as in the slide examp e,&(e.departme t id = d.department_id) is |
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optional. So, even ON e.department id = d.department_id will work. |
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Note: SQL Developer suffixes a ‘ 1’ to differ ntiate between the two department_ids. |
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Use |
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Internal |
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Oracle |
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In this example, the DEPARTMENT_ID columns in the EMPLOYEES and DEPARTMENTS table are joined using the ON clause. Wherever a department ID in the EMPLOYEES table equals a department ID in the DEPARTMENTS table, the row is returned. The t ble alias is necessary to qualify the matching column_names.
Oracle Database 11g: SQL Fundamentals I 6 - 16
Creating Three-Way Joins with the ON Clause
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SELECT |
employee_id, city, department_name |
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FROM |
employees e |
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JOIN |
departments d |
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ON |
d.department_id = e.department_id |
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JOIN |
locations l |
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ON |
d.location_id = l.location_id; |
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… |
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Copyright © 2009, Oracle. All rights reserved. |
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Creating Three-Way Joins with the ON Clause |
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Oracle |
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A three-way join is a join of three tables. In SQL:1999–compliant syntax, joins are performed from left to right. So, the first join to be performed is EMPLOYEES JOIN DEPARTMENTS. The first join
condition can reference columns in EMPLOYEES and DEPARTMENTS but cannot reference columns |
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in LOCATIONS. The second join condition can reference columns from all three tables. |
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Note: The code example in the slide can also be accomplished with the USING clause: |
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SELECT e.employee_id, |
&l.city, d.department_name |
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Internal |
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FROM employees e |
Use |
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JOIN departments d |
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USING (departm nt id) |
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JOIN loca ions l |
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USING (location id) |
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Oracle |
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Oracle Database 11g: SQL Fundamentals I 6 - 17