1 Chapter 2 Basic SQL SELECT Statements

2 Chapter Objectives Distinguish between an RDBMS and an ORDBMS Identify keywords, mandatory clauses, and optional clauses in a SELECT statement Select and view all columns of a table Select and view one column of a table

3 Chapter Objectives Display multiple columns of a table Use a column alias to clarify the contents of a particular column Perform basic arithmetic operations in the SELECT clause

4 Chapter Objectives Remove duplicate lists, using either the DISTINCT or UNIQUE keyword Combine fields, literals, and other data Format output

5 Relational Database Management System (RDBMS) An RDBMS is the software program used to create the database and it allows you to enter, manipulate, and retrieve data

6 Object Relational Database Management System (ORDBMS) Same as an RDBMS except it can be used to reference objects such as maps and object fields

7 SELECT Statement Syntax SELECT statements are used to retrieve data from the database Syntax gives the basic structure, or rules, for a command

8 SELECT Statement Syntax Optional clauses and keywords are shown in brackets

9 SELECT Statement Syntax SELECT and FROM clauses are required SELECT clause identifies column(s) FROM clause identifies table(s) Each clause begins with a keyword

10 Selecting All Data in a Table Substitute an asterisk for the column names in a SELECT clause

11 Selecting One Column from a Table Enter column name in SELECT clause

12 Selecting Multiple Columns from a Table Separate column names with a comma

13 Operations Within the SELECT Statement Column alias can be used for column headings Perform arithmetic operations Suppress duplicates Concatenate data

14 Column Alias List after column heading AS keyword is optional Enclose in double quotation marks: –If it contains blank space(s) –If it contains special symbol(s) –To retain case

15 Column Alias Example

16 Arithmetic Operations Executed left to right Multiplication and division are solved first Addition and subtraction are solved last Override order with parentheses

17 Example Arithmetic Operation with Column Alias

18 Suppressing Duplicates Enter DISTINCT or UNIQUE after SELECT keyword

19 Concatenation Can combine data with string literal Use concatenation operator, || Allows use of column alias

20 Concatenation Example