The document provides an overview of basic SQL statements and capabilities. It discusses using SELECT statements to project columns, select rows, and join tables. It also covers arithmetic expressions, column aliases, concatenation, and eliminating duplicate rows. SQL statements are executed through the SQL*Plus environment, which allows editing, saving, and running SQL code and commands.

1. Writing Basic SQL Statements

2. ObjectivesAfter completing this lesson, you should be able to do the following:List the capabilities of SQL SELECT statementsExecute a basic SELECT statementDifferentiate between SQL statements and SQL*Plus commands

3. Capabilities of SQL SELECT StatementsProjectionSelectionTable 1Table 1JoinTable 2Table 1

4. Basic SELECT StatementSELECT [DISTINCT] {*, column [alias],...}FROMtable;SELECT identifies what columns.FROM identifies which table.

5. Writing SQL StatementsSQL statements are not case sensitive. SQL statements can be on one ormore lines.Keywords cannot be abbreviated or split across lines.Clauses are usually placed on separate lines.Tabs and indents are used to enhance readability.

6. Selecting All ColumnsSQL> SELECT *2 FROM dept; DEPTNO DNAME LOC--------- -------------- -------------10 ACCOUNTING NEW YORK20 RESEARCH DALLAS30 SALES CHICAGO40 OPERATIONS BOSTON

7. Selecting Specific ColumnsSQL> SELECT deptno, loc2 FROM dept; DEPTNO LOC--------- -------------10 NEW YORK20 DALLAS30 CHICAGO40 BOSTON

8. Column Heading DefaultsDefault justificationLeft: Date and character dataRight: Numeric dataDefault display: Uppercase

9. Arithmetic ExpressionsCreate expressions on NUMBER and DATE data by using arithmetic operators.Operator+-* / DescriptionAddSubtract Multiply Divide

10. Using Arithmetic OperatorsSQL> SELECT ename, sal, sal+3002 FROMemp;ENAME SAL SAL+300---------- --------- ---------KING 50005300BLAKE 28503150CLARK 24502750JONES 29753275MARTIN 12501550ALLEN 16001900...14 rows selected.

11. 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.

12. Operator PrecedenceSQL> SELECT ename, sal, 12*sal+1002 FROM emp;ENAME SAL 12*SAL+100---------- --------- ----------KING 500060100BLAKE 285034300CLARK 245029500JONES 297535800MARTIN 125015100ALLEN 160019300...14 rows selected.

13. Using ParenthesesSQL> SELECT ename, sal, 12*(sal+100)2 FROM emp;ENAME SAL 12*(SAL+100)---------- --------- -----------KING 500061200BLAKE 285035400CLARK 245030600JONES 297536900MARTIN 125016200...14 rows selected.

14. Defining a Null ValueA 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, comm2 FROMemp;ENAME JOB COMM---------- --------- ---------KING PRESIDENTBLAKE MANAGER...TURNER SALESMAN 0...14 rows selected.

15. Null Values in Arithmetic ExpressionsArithmetic expressions containing a null value evaluate to null.SQL> select ename, 12*sal+comm 2 from emp3 WHERE ename='KING';ENAME 12*SAL+COMM ---------- -----------KING

16. Defining a Column AliasRenames a column headingIs useful with calculationsImmediately follows column name; optional AS keyword between column name and aliasRequires double quotation marks if it contains spaces or special characters or is case sensitive

17. Using Column AliasesName Annual Salary------------- -------------...SQL> SELECT ename AS name, sal salary2 FROM emp;NAME SALARY------------- ---------...SQL> SELECT ename "Name",2 sal*12 "Annual Salary"3 FROM emp;

18. Concatenation OperatorConcatenates columns or character strings to other columns Is represented by two vertical bars (||)Creates a resultant column that is a character expression

19. Using the Concatenation OperatorSQL> SELECTename||job AS "Employees"2 FROM emp;Employees-------------------KINGPRESIDENTBLAKEMANAGERCLARKMANAGERJONESMANAGERMARTINSALESMANALLENSALESMAN...14 rows selected.

20. Literal Character StringsA 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.

21. Using Literal Character StringsSQL> SELECT ename||' '||'is a'||' '||job 2AS "Employee Details"3 FROM emp;Employee Details-------------------------KING is a PRESIDENTBLAKE is a MANAGERCLARK is a MANAGERJONES is a MANAGERMARTIN is a SALESMAN...14 rows selected.

22. Duplicate RowsThe default display of queries is all rows, including duplicate rows.SQL> SELECT deptno2 FROM emp; DEPTNO---------10301020...14 rows selected.

23. Eliminating Duplicate RowsEliminate duplicate rows by using the DISTINCT keyword in the SELECT clause.SQL> SELECT DISTINCT deptno2 FROM emp; DEPTNO---------102030

24. SQL and SQL*Plus InteractionSQL StatementsSQL StatementsServerQuery ResultsSQL*Plus CommandsFormatted ReportBufferSQL*Plus

25. SQL Statements Versus SQL*Plus Commands SQL A language

26. ANSI standard

27. Keyword cannot be abbreviated

28. Statements manipulate data and table definitions in the databaseSQL*PlusAn environment

29. Oracle proprietary

30. Keywords can be abbreviated

31. Commands do not allow manipulation of values in the databaseSQLstatementsSQLbufferSQL*PluscommandsSQL*Plusbuffer

32. 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 bufferto edit.Overview of SQL*Plus

33. Logging In to SQL*PlusFrom Windows environment:From command line: sqlplus [username[/password [@database]]]

34. Displaying Table StructureUse the SQL*Plus DESCRIBE command to display the structure of a table.DESC[RIBE] tablename