Copyright  Oracle Corporation, All rights reserved. Writing Basic SQL Statements

1-2 Copyright  Oracle Corporation, All rights reserved. Capabilities of SQL SELECT Statements Selection Projection Table 1 Table 2 Table 1 Join

1-3 Copyright  Oracle Corporation, All rights reserved. Basic SELECT Statement SELECT[DISTINCT] {*, column [alias],...} FROMtable; SELECT[DISTINCT] {*, column [alias],...} FROMtable; SELECT identifies what columns. FROM identifies which table. SELECT identifies what columns. FROM identifies which table.

1-4 Copyright  Oracle Corporation, All rights reserved. Writing SQL Statements SQL statements are not case sensitive. SQL statements can be on one or more lines. Keywords cannot be abbreviated or split across lines. Clauses are usually placed on separate lines. Tabs and indents are used to enhance readability. SQL statements are not case sensitive. SQL statements can be on one or more lines. Keywords cannot be abbreviated or split across lines. Clauses are usually placed on separate lines. Tabs and indents are used to enhance readability.

1-5 Copyright  Oracle Corporation, All rights reserved. Selecting All Columns DEPTNO DNAME LOC ACCOUNTING NEW YORK 20 RESEARCH DALLAS 30 SALES CHICAGO 40 OPERATIONS BOSTON SQL> SELECT * 2 FROM dept;

1-6 Copyright  Oracle Corporation, All rights reserved. Selecting Specific Columns DEPTNO LOC NEW YORK 20 DALLAS 30 CHICAGO 40 BOSTON SQL> SELECT deptno, loc 2 FROM dept;

1-7 Copyright  Oracle Corporation, All rights reserved. Arithmetic Expressions Create expressions on NUMBER and DATE data by using arithmetic operators. Operator + - * / Description Add Subtract Multiply Divide

1-8 Copyright  Oracle Corporation, All rights reserved. Using Arithmetic Operators SQL> SELECT ename, sal, sal FROMemp; ENAME SAL SAL KING BLAKE CLARK JONES MARTIN ALLEN rows selected.

1-9 Copyright  Oracle Corporation, All rights reserved. Operator Precedence Multiplication and division take priority over addition and subtraction. Operators of the same priority are evaluated from left to right. Parentheses are used to force prioritized evaluation and to clarify statements. Multiplication and division take priority over addition and subtraction. Operators of the same priority are evaluated from left to right. Parentheses are used to force prioritized evaluation and to clarify statements. ** //++__

1-10 Copyright  Oracle Corporation, All rights reserved. Operator Precedence SQL> SELECT ename, sal, 12*sal FROM emp; ENAME SAL 12*SAL KING BLAKE CLARK JONES MARTIN ALLEN rows selected.

1-11 Copyright  Oracle Corporation, All rights reserved. Using Parentheses SQL> SELECT ename, sal, 12*(sal+100) 2 FROM emp; ENAME SAL 12*(SAL+100) KING BLAKE CLARK JONES MARTIN rows selected.

1-12 Copyright  Oracle Corporation, All rights reserved. Defining a Null Value A null is a value that is unavailable, unassigned, unknown, or inapplicable. A null is not the same as zero or a blank space. A null is a value that is unavailable, unassigned, unknown, or inapplicable. A null is not the same as zero or a blank space. SQL> SELECT ename, job, comm 2 FROMemp; ENAME JOB COMM KING PRESIDENT BLAKE MANAGER... TURNER SALESMAN rows selected.

1-13 Copyright  Oracle Corporation, All rights reserved. Null Values in Arithmetic Expressions Arithmetic expressions containing a null value evaluate to null. SQL> select ename, 12*sal+comm 2 from emp 3 WHERE ename='KING'; ENAME 12*SAL+COMM KING

1-14 Copyright  Oracle Corporation, All rights reserved. Defining a Column Alias Renames a column heading Is useful with calculations Immediately follows column name; optional AS keyword between column name and alias Requires double quotation marks if it contains spaces or special characters or is case sensitive Renames a column heading Is useful with calculations Immediately follows column name; optional AS keyword between column name and alias Requires double quotation marks if it contains spaces or special characters or is case sensitive

1-15 Copyright  Oracle Corporation, All rights reserved. Using Column Aliases SQL> SELECT ename AS name, sal salary 2 FROM emp; NAME SALARY SQL> SELECT ename "Name", 2 sal*12 "Annual Salary" 3 FROM emp; Name Annual Salary

1-16 Copyright  Oracle Corporation, All rights reserved. Concatenation Operator Concatenates columns or character strings to other columns Is represented by two vertical bars (||) Creates a resultant column that is a character expression Concatenates columns or character strings to other columns Is represented by two vertical bars (||) Creates a resultant column that is a character expression

1-17 Copyright  Oracle Corporation, All rights reserved. Using the Concatenation Operator SQL> SELECTename||job AS "Employees" 2 FROM emp; Employees KINGPRESIDENT BLAKEMANAGER CLARKMANAGER JONESMANAGER MARTINSALESMAN ALLENSALESMAN rows selected.

1-18 Copyright  Oracle Corporation, All rights reserved. Literal Character Strings A literal is a character, expression, or number included in the SELECT list. Date and character literal values must be enclosed within single quotation marks. Each character string is output once for each row returned. A literal is a character, expression, or number included in the SELECT list. Date and character literal values must be enclosed within single quotation marks. Each character string is output once for each row returned.

1-19 Copyright  Oracle Corporation, All rights reserved. Using Literal Character Strings Employee Details KING is a PRESIDENT BLAKE is a MANAGER CLARK is a MANAGER JONES is a MANAGER MARTIN is a SALESMAN rows selected. Employee Details KING is a PRESIDENT BLAKE is a MANAGER CLARK is a MANAGER JONES is a MANAGER MARTIN is a SALESMAN rows selected. SQL> SELECT ename||' '||'is a'||' '||job 2 AS "Employee Details" 3 FROM emp;

1-20 Copyright  Oracle Corporation, All rights reserved. Duplicate Rows The default display of queries is all rows, including duplicate rows. SQL> SELECT deptno 2 FROM emp; SQL> SELECT deptno 2 FROM emp; DEPTNO rows selected.

1-21 Copyright  Oracle Corporation, All rights reserved. Eliminating Duplicate Rows Eliminate duplicate rows by using the DISTINCT keyword in the SELECT clause. SQL> SELECT DISTINCT deptno 2 FROM emp; DEPTNO

1-22 Copyright  Oracle Corporation, All rights reserved. SQL and SQL*Plus Interaction SQL*Plus SQL Statements Buffer Server Query Results SQL*Plus Commands Commands Formatted Report

1-23 Copyright  Oracle Corporation, All rights reserved. SQL Statements Versus SQL*Plus Commands SQLstatements SQL A languageA language ANSI standardANSI standard Keyword cannot be abbreviatedKeyword cannot be abbreviated Statements manipulate data and table definitions in the databaseStatements manipulate data and table definitions in the databaseSQL*Plus An environmentAn environment Oracle proprietaryOracle proprietary Keywords can be abbreviatedKeywords can be abbreviated Commands do not allow manipulation of values in the databaseCommands do not allow manipulation of values in the database SQLbufferSQL*PluscommandsSQL*Plusbuffer

1-24 Copyright  Oracle Corporation, All rights reserved. Log in to SQL*Plus. Describe the table structure. Edit your SQL statement. Execute SQL from SQL*Plus. Save SQL statements to files and append SQL statements to files. Execute saved files. Load commands from file to buffer to edit. Log in to SQL*Plus. Describe the table structure. Edit your SQL statement. Execute SQL from SQL*Plus. Save SQL statements to files and append SQL statements to files. Execute saved files. Load commands from file to buffer to edit. Overview of SQL*Plus

1-25 Copyright  Oracle Corporation, All rights reserved. Logging In to SQL*Plus From Windows environment:From Windows environment: From command line:From command line: sqlplus [username[/password sqlplus [username[/password From Windows environment:From Windows environment: From command line:From command line: sqlplus [username[/password sqlplus [username[/password

1-26 Copyright  Oracle Corporation, All rights reserved. Displaying Table Structure Use the SQL*Plus DESCRIBE command to display the structure of a table. DESC[RIBE] tablename

1-27 Copyright  Oracle Corporation, All rights reserved. Displaying Table Structure SQL> DESCRIBE dept Name Null? Type DEPTNO NOT NULL NUMBER(2) DNAME VARCHAR2(14) LOC VARCHAR2(13) Name Null? Type DEPTNO NOT NULL NUMBER(2) DNAME VARCHAR2(14) LOC VARCHAR2(13)

1-28 Copyright  Oracle Corporation, All rights reserved. SQL*Plus File Commands SAVE filename GET filename START filename EDIT filename SPOOL filename SAVE filename GET filename START filename EDIT filename SPOOL filename

1-29 Copyright  Oracle Corporation, All rights reserved. Summary Use SQL*Plus as an environment to: Execute SQL statements Edit SQL statements Use SQL*Plus as an environment to: Execute SQL statements Edit SQL statements SELECT[DISTINCT] {*,column [alias],...} FROMtable; SELECT[DISTINCT] {*,column [alias],...} FROMtable;

1-30 Copyright  Oracle Corporation, All rights reserved. Practice Overview Selecting all data from different tables Describing the structure of tables Performing arithmetic calculations and specifying column names Using SQL*Plus editor Selecting all data from different tables Describing the structure of tables Performing arithmetic calculations and specifying column names Using SQL*Plus editor