SQL Part I Yong Choi School of Business
SQL – Part I Yong Choi School of Business CSU, Bakersfield
Study Objectives • Understand the basic commands and functions of SQL • Learn how SQL is used for data manipulation (to add, modify, delete, and retrieve data) • Learn how to use SQL to query a database to extract useful information • Learn how SQL is used for data administration (to create tables, indexes, and views) • Practice SQL 2
Ideal Database Language Requirements • Create database and table structures. – SQL has a data definition component that gives us the ability to meet this requirement. • Manage the data component of the database. – SQL gives us a set of commands to add, update, and delete data within the database tables. • Provide detailed data query capability. – "Standard" SQL uses a set of approximately thirty commands that allow us to retrieve data and to convert the raw data into useful information. 3
Brief History of SQL • Standard Query Language (SQL) is the relational model’s standard language. • The original version of SQL was developed at IBM's San Jose Research Laboratory. This language, originally called Sequel. The Sequel language has evolved since then, and its name has changed to SQL (Structured Query Language). • In 1986, the American National Standards Institute (ANSI) published an SQL standard. – In 1992, work was completed on a significantly revised version of the SQL standard (SQL-92). 4
Introduction to SQL • SQL is relatively easy to learn – SQL commands set has a basic vocabulary of less than 100 words. • SQL is a nonprocedural language. So, it is much easier to use. – Its user merely commands what is to be done without having to worry about how it's to be done. – Procedural language: COBOL, C, or Pascal. • See SQL by “Restaurant” DB on the class website 5
Basic Structure of SQL Queries • • • SELECT <attribute list> FROM <table list> WHERE <condition> GROUP BY < grouping attribute(s)> HAVING <group condition> ORDER BY <attribute list> 6
The SELECT and FROM Statement • The SELECT statement is used to select data from a table. The tabular result is stored in a result table (called the result set). The FROM statement is used to select tables. • Syntax: – SELECT column_name(s) – FROM table_name • To select all columns from a table, use a * symbol instead of column names: – SELECT * FROM table_name 7
The WHERE Statement • To conditionally select data from a table, a WHERE clause can be added to the SELECT statement. • Syntax: – SELECT column – FROM table – WHERE column operator value 8
Typical Data Types • INTEGER: Numbers without a decimal point • SMALLINT: Uses less space than INTEGER • DECIMAL(p, q): P number of digits; q number of decimal places • CHAR(n): Character string n places long • DATE: Dates in DD-MON-YYYY or MM/DD/YYYY 9
Semicolon after SQL Statements? • Semicolon is the standard way to separate each SQL statement in database systems that allow more than one SQL statement to be executed in the same call to the server. • MS Access and SQL Server do not require to put a semicolon after each SQL statement, but other database SQLs force you to use it such as Oracle. So, you must use a semicolon for this class. – Access SQL commands are not case sensitive (including table and attribute names) but try to follow exact names for better readability. – Download SQL data file form the class web site. 10
Customer. Num Customer. Name Street City State Zip Balance 148 Al's Appliance and Sport 2837 Greenway Fillmore FL 33336 $6, 550 Credit. Limit $7, 500 Rep. Num 20 Order. Line Order. Num Part. Num 21608 AT 94 Num. Ordered Quoted. Price 11 $21. 95 Orders Order. Num 21608 Order. Date 10/20/2003 Customer. Num 148 Part. Num Description AT 94 Iron On. Hand 50 Class Warehouse HW 3 Price $24. 95 Rep. Num Last. Name First. Name Street City State Zip 20 Kaiser Valerie 624 Randall Grove FL 33321 Commission $20, 542. 50 Rate 0. 05 11
How to proceed…. • First, we will try to generate query using Microsoft Access QBE. – Visual way to generate query – And review SQL thru “SQL View” – Then, delete the query • And then, we will try to generate query again using SQL – SQL programming is provided. – So, just copy and paste 12
Example 2 • Example 2: Save as example 2 – List the number, name, and balance of all customers. 13
Example 2 14
Example 2 SELECT Customernum, Customer. Name, Balance FROM Customer; 15
Example 3 • Example 3: Save as example 3 – List the complete Part table. – Use of “ * “ 16
Example 3 17
Example 3 SELECT * FROM Part; 18
Oracle 7. 0 SQL Example SQL> select * from employee; EMP_ID EMP_LNAME EMP_FNAME EMP_SALARY EMP_DEPT_NO ---------- -----1 Kim John 1000 100 2 Johnson Steve 1200 100 3 Jonson Paul 1100 200 4 Lee Jim 1100 200 5 Basinger Jon 1300 6 Stone Sharon 1000 6 rows selected. 19
SQL Example – WHERE clause • Example 4: Save as example 4 – List the name of every customers with $10, 000 credit limit. • Credit limit must be equal to $10000 20
Example 4 SQL Query with Where Condition 21
Example 4 SELECT Customername FROM Customer WHERE Credit. Limit=10000; 22
SQL Example – WHERE clause • Example 5: Save as example 5 – Find the name of customer 148. 23
Example 5 SQL Query to Find Customer 148 24
SQL Comparison Operators For WHERE clause NOT Warehouse =‘ 3’ LIKE: LIKE ‘a*’, LIKE ‘*s’, Like ‘*Oxford*’ (NOT) BETWEEN 45000 AND 78000 (NOT) IN (123, 345) 25
SQL Examples • Example 6: Save as example 6 – Find the customer name for every customer located in the city of Grove 26
Example 6 27
SQL Examples • Example 7: Save as example 7 – List the number, name, credit limit, and balance for customers with credit limits that exceed their balances. 28
Example 7 29
SQL Examples – Compound Conditions • Example 8: Save as example 8 – List the description of all parts that are located in warehouse 3 and for which there are more than 20 units on hand. 30
Example 8 SQL Query with Compound Condition using ‘AND’ 31
SQL Examples – Compound Conditions • Example 9: Save as example 9 – List the descriptions of all parts that are located in warehouse 3 or for which there are more than 20 units on hand. 32
Example 9 SQL Query using ‘OR’ 33
SQL Examples • Example 10: Save as example 10 – List the description of all parts that are not in warehouse 3. – Use “NOT” (i. e. , where NOT A = 100; ) 34
Example 10 SQL Query using ‘NOT’ 35
SQL Examples • Example 11: Save as example 11 – List the number, name, and balance of all customers with balances greater than or equal to $1, 000 and less than or equal to $5, 000. – (NOT) BETWEEN 45000 AND 78000 36
Example 11 Query with ‘BETWEEN’ Operator 37
SQL Examples – Computed Field • Computed field can involve: – addition(+), subtraction(-), Multiplication(*), or division (/) • Example 12: Save as example 12 – List the number, name and available credit for all customers. – Use “AS” for assigning a new field name 38
Example 12 SQL Query with Computed Field 39
SQL Examples – Computed Field • Computed field can involve: – addition(+), subtraction(-), Multiplication(*), or division (/) • Example 13: Save as example 13 – List the number, name, and available credit for all customers with credit limits that exceed their balances. 40
Example 13 SQL Query with Computed Field and Condition 41
SQL Examples – LIKE and IN • Example 14: Save as example 14 – List the number, name, and complete address of every customer located on a street that contain the letters “Oxford. ” • Customer names begin with B: Like B* • Customer names end with E: Like *E • Fine exact customer last name: like ‘*Choi*’ 42
Example 14 SQL Query with ‘LIKE’ Operator 43
SQL Examples – LIKE and IN • Example 15: Save as example 15 – List the number, name, and credit limit for every customer with a credit of $7, 500, $10, 000, or $15, 000. – IN (7500, 10000, 15000); 44
Example 15 SQL Query with ‘IN’ Operator 45
SQL Examples • Default value of ORDER BY: ascending • Example 16: Save as example 16 – List the number, name, and credit limit of all customers. Sort the customers by name in ascending order. 46
Example 16 SQL Query to Sort Data 47
SQL Examples • Default value of ORDER BY: ascending • Example 17: Save as example 17 – List the number, name, and credit limit of all customers. Sort the customers by name (minor) in ascending order within credit limit (major) in descending order. – What about this case? • customer name (minor) and credit limit (major) 48
Example 17 SQL Query to Sort on Multiple Fields 49
- Slides: 49