SQLSQL BasicsBasics PartPart IIII

JonathanJonathan MillerMiller LearningLearning SQLSQL SeriesSeries

1 ItemsItems ToTo bebe CoveredCovered

„ Review of SQL Basics I „ Join Types „ Inner & Outer Joins „ Self-Joins „ Working With Multiple Queries „ UNION, INTERSECT, MINUS „ Subqueries & Correlated Subqueries „ EXISTS & NOT EXISTS „ Functions „ Group „ String „ Date „ Number „ Participants Questions & Answers (hopefully!)

2 ReviewReview ofof SQLSQL BasicsBasics II

„ StructureStructure ofof aa SQLSQL StatementStatement SELECTSELECT column(scolumn(s FROMFROM table(stable(s )) WHEREWHERE )) ORDERORDERcondition(s condition(s BYBY column(scolumn(s)) )) OptionalOptional ElementsElements

3 CartesianCartesian // SimpleSimple JoinJoin SELECT mo_id, poc, parameter_desc FROM monitors, parameters

MONITORS PARAMETERS

MO_ID SI_SI_ID PA_PARAMETER_CODE POC

Parameter_Code Parameter_Desc 1 1 44201 1

44201 Ozone 2 1 42101 1 3 1 42101 2 42101 CO 4 2 81102 1

42401 SO2 5 2 44201 1

81102 PM10 6 3 42401 1 4 PrimaryPrimary && ForeignForeign KeysKeys

„ PrimaryPrimary KeyKey (s)(s) „ ColumnsColumns onon aa TableTable thatthat UniquelyUniquely IdentifyIdentify aa RecordRecord onon thethe TableTable „ CanCan bebe composedcomposed ofof 11 oror moremore columnscolumns „ ForeignForeign KeyKey (s)(s) „ ColumnColumn onon aa tabletable thatthat referencesreferences thethe PrimaryPrimary KeyKey ofof anotheranother TableTable „ CanCan bebe composedcomposed ofof oneone oror moremore columnscolumns

5 InnerInner JoinJoin BetweenBetween 22 TablesTables SELECT mo_id, poc, parameter_desc FROM monitors, parameters WHERE pa_parameter_code = parameter_code

MONITORS PARAMETERS

MO_ID SI_SI_ID PA_PARAMETER_CODE POC

Parameter_Code Parameter_Desc 1 1 44201 1

44201 Ozone 2 1 42101 1 3 1 42101 2 42101 CO 4 2 81102 1

42401 SO2 5 2 44201 1

81102 PM10 6 3 424016 1 JoiningJoining TablesTables TogetherTogether

„ JoinsJoins BetweenBetween TablesTables areare UsuallyUsually BasedBased onon PrimaryPrimary // ForeignForeign KeysKeys „ MakeMake SureSure JoinsJoins BetweenBetween AllAll TablesTables inin thethe FROMFROM ClauseClause ExistExist „ ListList JoinsJoins BetweenBetween TablesTables BeforeBefore OtherOther SelectionSelection ElementsElements

7 AliasesAliases

„ ““ShorthandShorthand”” forfor TableTable oror ColumnColumn ReferencesReferences „ SELECTSELECT AliasesAliases AppearAppear asas ColumnColumn HeadersHeaders inin thethe OutputOutput „ AliasesAliases CannotCannot bebe KeywordsKeywords (SELECT,(SELECT, FROM,FROM, WHERE,WHERE, etc)etc)

8 JoinJoin TypesTypes andand PuttingPutting MultipleMultiple SQLSQL SelectSelect StatementsStatements TogetherTogether

QUALIFIER_ SITES RAW_DATA DETAILS

MONITOR_ MONITORS PROTOCOLS

9 JoinJoin TypesTypes

„ SimpleSimple Join:Join: „ No links made between multiple tables „ RESULT: Cartesian Product „ InnerInner JoinJoin „ TABLE1.Foreign Key = TABLE2.Primary Key „ RESULT: 1 record for each match between the 2 tables „ OuterOuter JoinJoin „ TABLE1.Foreign Key = TABLE2.Primary Key(+) „ RESULT: 1 record for each match between the 2 tables AND 1 record for each where the record only exists in TABLE1

10 jm1

OuterOuter JoinsJoins

„ PlacePlace aa ““(+)(+)”” NextNext toto thethe ColumnColumn NameName inin thethe WHEREWHERE clauseclause ofof thethe SHORTER tabletable „ WhereWhere toto Use:Use: „ WhenWhen youyou havehave nullnull valuesvalues inin aa columncolumn thatthat youyou areare joiningjoining onon „ WhenWhen aa parentparent recordrecord maymay notnot havehave aa childchild recordrecord „ AA TableTable CanCan OnlyOnly BeBe OuterOuter JoinedJoined toto OneOne OtherOther TableTable withinwithin aa GivenGiven QueryQuery

11 OuterOuter JoinJoin ExamplesExamples

12 SelfSelf JoinsJoins

Parent Record A

Parent Record B

Parent Record C

Parent Record D

13 WhatWhat isis ItIt

„ SpecialSpecial CaseCase ofof anan InnerInner JoinJoin „ UseUse WhenWhen YouYou needneed ““RowsRows”” ofof aa ChildChild RecordRecord toto AppearAppear asas ““ColumnsColumns”” „ SpecifySpecify thethe SameSame TableTable MultipleMultiple TimesTimes inin thethe ““FROMFROM”” ClauseClause „ GiveGive EachEach InstanceInstance anan AliasAlias „ InIn thethe ““WHEREWHERE”” Clause,Clause, SpecifySpecify thethe SpecificSpecific ValueValue DesiredDesired

14 SelfSelf JoinJoin ExampleExample

15 Union,Union, Intersection,Intersection, MinusMinus

A B C

16 WhatWhat DoesDoes itit Do?Do?

„ ProcessesProcesses thethe ResultsResults ofof SeparateSeparate QueriesQueries IntoInto aa SingleSingle ReturnReturn „ UNIONUNION:: EverythingEverything fromfrom QueryQuery 11 ++ EverythingEverything fromfrom QueryQuery 22 „ INTERSECTION:INTERSECTION: OnlyOnly recordsrecords wherewhere thethe resultsresults betweenbetween QueryQuery 11 andand QueryQuery 22 areare thethe samesame „ MINUS:MINUS: EverythingEverything fromfrom QueryQuery 11 –– MatchingMatching RecordsRecords fromfrom QueryQuery 22

17 WhatWhat WouldWould bebe Returned?Returned?

132 A 5 B 4 6

QUESTION: C ANSWER: 1. A UNION B 7 1, 2, 3, 4, 5, 6 2. A MINUS B 1, 4 3. A INTERSECT (B MINUS C) 2

4. C UNION (B INTERSECT A) 2, 4, 5, 6,18 7 RulesRules forfor TheseThese QueriesQueries

„ EachEach QueryQuery MustMust ContainContain thethe samesame NumberNumber ofof andand TypeType ofof DataData ElementsElements Select arithmetic_mean From Annual_Summaries Union Select max_value From Summary_Maximums „ OnlyOnly UniqueUnique OccurrencesOccurrences ofof thethe RecordsRecords willwill bebe RetunedRetuned UnlessUnless youyou SpecifySpecify thethe ““ALLALL”” KeywordKeyword SELECT ALL arithmetic_mean FROM Annual_Summaries Union SELECT max_value FROM Summary_Maximums „ IfIf youyou wantwant thethe DataData Sorted,Sorted, MustMust bebe ReferencedReferenced byby ColumnColumn PositionPosition

19 UNION,UNION, INTERSECT,INTERSECT, MINUSMINUS ExamplesExamples

20 SubqueriesSubqueries && CorrelatedCorrelated SubqueriesSubqueries

21 SubqueriesSubqueries

„ AA SubquerySubquery isis SimplySimply aa QueryQuery WithinWithin AnotherAnother QueryQuery „ Used as a Filtering Mechanism „ Additional Queries Appear in the WHERE Clause „ Can be Nested up to 16 Levels „ AA CorrelatedCorrelated SubquerySubquery isis aa SubquerySubquery WhenWhen thethe 22nd QueryQuery ReferencesReferences aa columncolumn FromFrom thethe PrimaryPrimary QueryQuery

22 SubquerySubquery ExamplesExamples

23 ExistsExists AndAnd NOTNOT EXISTSEXISTS

24 EXISTSEXISTS andand NOTNOT EXISTSEXISTS

„ SpecialSpecial SubquerySubquery UsedUsed inin thethe WHEREWHERE ClauseClause „ LooksLooks forfor thethe ExistenceExistence ofof ANYANY RecordRecord inin thethe SubquerySubquery „ CanCan bebe MuchMuch FasterFaster thanthan UsingUsing anan ““ININ”” ClauseClause SinceSince itit OnlyOnly NeedsNeeds toto FindFind 11 RecordRecord toto SatisfySatisfy thethe ConditionCondition

25 EXISTSEXISTS andand NOTNOT EXISTSEXISTS ExampleExample

26 FunctionsFunctions

27 WhatWhat isis aa Function?Function?

„ StoredStored SoftwareSoftware thatthat ManipulatesManipulates SubmittedSubmitted ElementsElements andand ReturnsReturns SomeSome ValueValue „ MayMay byby aa SQLSQL StandardStandard FunctionFunction (SUBSTR)(SUBSTR) „ CouldCould bebe ApplicationApplication SpecificSpecific (GET_METHOD)(GET_METHOD) „ GenerallyGenerally TwoTwo CategoriesCategories „ CreationCreation ofof NewNew ObjectsObjects FromFrom OldOld OnesOnes „ DescriptionsDescriptions ofof ObjectsObjects

28 FunctionFunction NotationNotation

„ FUNCTION(parameterFUNCTION(parameter {{datatypedatatype},}, [optional[optional parameters])parameters]) „ DatatypesDatatypes „ VARCHAR2VARCHAR2 ((‘‘AppleApple’’,, ‘‘SampleSample TextText **’’,, ‘‘12341234’’)) „ NUMBERNUMBER (1,(1, 1.03,1.03, --15)15) „ DATEDATE –– WeWe’’llll talktalk aboutabout thisthis oneone laterlater……

29 TypesTypes ofof FunctionsFunctions

„ StringString FunctionsFunctions „ MathematicalMathematical FunctionsFunctions „ SingleSingle--ValueValue FunctionsFunctions „ GroupGroup--ValueValue FunctionsFunctions „ ListList FunctionsFunctions „ ConversionConversion // TransformationTransformation FunctionsFunctions „ DateDate FunctionsFunctions

30 WhereWhere CanCan II UseUse Functions?Functions?

„ SELECTSELECT StatementStatement „ SELECTSELECT INITCAP(agency_descINITCAP(agency_desc)) FROMFROM agenciesagencies „ WHEREWHERE StatementStatement SELECT * FROM sites WHERE SUBSTR(lut_land_use_type, 1) = ‘MOBILE’

31 DUALDUAL TableTable

„ RealReal OracleOracle TableTable WithWith aa SingleSingle RowRow „ UsedUsed WhenWhen AllAll ElementsElements inin thethe SELECTSELECT andand WHEREWHERE ClausesClauses dodo notnot ReferenceReference AnyAny TablesTables

SELECTSELECT ‘‘AA’’ FROMFROM DUALDUAL „ Result:Result: ““AA””

32 CommonCommon StringString FunctionsFunctions

„ |||| „ INITCAP(StringINITCAP(String)) „ INSTR(StringINSTR(String,, setset [,[, startstart [,[, occurrence]occurrence] ])]) „ LENGTH(StringLENGTH(String)) „ LOWER(StringLOWER(String)) // UPPER(StringUPPER(String)) „ LPAD(String, Length [, ‘set’]) / RPAD(String, Length [, ‘set’]) „ LTRIM(StringLTRIM(String [,[, ‘‘setset’’])]) // RTRIM(StringRTRIM(String [,[, ‘‘setset’’])]) „ SUBSTR(StringSUBSTR(String,, StartStart [,count])[,count])

33 ConcatenateConcatenate (||)(||)

„ GluesGlues twotwo StringsStrings TogetherTogether

SELECTSELECT ‘‘GoGo’’ |||| ‘‘ WOLFPACKWOLFPACK’’ FROMFROM DUALDUAL

„ Results:Results:““GoGo WOLFPACKWOLFPACK””

34 INITCAP,INITCAP, UPPER,UPPER, LOWERLOWER

„ Deals with the Capitalization of Strings „ INITCAP – Capitalizes first letter of a string as well as after spaces, periods. Lower case for all other letters „ UPPER – All Upper Case „ LOWER – All Lower Case

SELECT INITCAP(‘gO woLFpack’), UPPER (‘gO woLFpack’), LOWER(‘gO woLFpack’) FROM dual

„ RESULTS: “Go Wolfpack”, “GO WOLFPACK”, “go wolfpack”

35 ““InIn StringString”” -- INSTRINSTR

„ Finds the Position of a String Within a String

SELECT INSTR(‘Go Wolfpack’, ‘ac’) FROM dual „ Results: 9

„ Optionally can tell it Where to Start and What Occurrence to Find

SELECT INSTR(‘Go Wolfpack’, ‘o’, 1, 2) FROM dual „ Results: 5

36 LENGTHLENGTH

„ TellsTells youyou HowHow LongLong aa StringString IsIs (Spaces(Spaces Count)Count)

SELECTSELECT LENGTH(LENGTH(‘‘GoGo WolfpackWolfpack’’)) FROMFROM dualdual „ Result:Result: 1111

37 LPADLPAD // RPADRPAD

„ “Pads” Out a String To a Given Length „ Defaults to Pad with a Space „ You May Optionally Specify What Character to Use

SELECT LPAD(‘Carrot’,10) FROM dual „ Result: “ Carrot”

SELECT RPAD(‘Carrot’,10, ‘x’) FROM dual „ Result: “Carrotxxxx”

38 LTRIMLTRIM // RTRIMRTRIM

„ Trims off a Set of Characters from Either the Left (LTRIM) or Right (RTRIM) of a String „ Keeps Trimming Until No More of the SET of Characters are Found

SELECT RTRIM(‘Go Wolfpack’, ‘k’) FROM DUAL „ Results: “Go Wolfpac”

SELECT LTRIM(‘Go Wolfpack’, ‘oGfW’) FROM dual „ Results: “lfpack”

39 SubstringSubstring -- SUBSTRSUBSTR

„ Clips out a Portion of a String „ May Tell it How Many Characters to Clip (Default is to clip to end of the string)

SELECT SUBSTR(‘Go Wolfpack’, 7) FROM dual „ Results: “pack”

SELECT SUBSTR(‘Go Wolfpack’, 7,3) FROM dual „ Results: “pac”

40 MathematicMathematic FunctionsFunctions

„ ABSABS –– AbsoluteAbsolute ValueValue „ SQRTSQRT –– SquareSquare RootRoot „ CEILCEIL // FLOORFLOOR –– „ TRUNCTRUNC –– TruncateTruncate SmallestSmallest IntegerInteger „ ListList FunctionsFunctions AboveAbove // BelowBelow ValueValue „ GREATEST (List) „ MODMOD –– ModulusModulus „ LEAST (List) „ POWERPOWER „ GroupGroup FunctionsFunctions „ ROUNDROUND „ AVG, COUNT, MAX, MIN, STDDV, SUM, VARIANCE

41 GroupGroup FunctionsFunctions By Size 7 11 4 2 1 1 Total Count By Color 1 3 5 3 24 By Color & Size

42 GroupGroup FunctionsFunctions ExampleExample

„ WhenWhen youyou useuse thethe GROUPGROUP functions,functions, youyou mustmust specifyspecify thethe breakingbreaking elementselements inin aa GROUPGROUP BYBY clauseclause „ TheseThese mustmust includeinclude allall nonnon--groupgroup functionfunction itemsitems inin youryour SELECTSELECT statementstatement „ SelectSelect thethe maximummaximum arithmeticarithmetic meanmean perper yearyear

SELECT annual_summary_year, MAX(annual_arithmetic_mean) FROM annual_summaries GROUP BY annual_summary_year

43 TransformationTransformation FunctionsFunctions

„ NVLNVL –– NullNull ValueValue FunctionFunction „ Default value to return if the column value is NULL „ DECODEDECODE –– SQLSQL versionversion ofof anan ““IFIF”” StatementStatement „ TypeType ConversionsConversions „ TO_DATE – Convert a String to a Date „ TO_NUMBER – Convert a String to a Number „ TO_CHAR – Convert a Date or Number to a String

44 NVLNVL && DECODEDECODE ExampleExample

„ HowHow dodo youyou selectselect aa TribalTribal SiteSite ID?ID? „ IFIF aa TribalTribal CodeCode existsexists forfor aa site,site, UseUse ““TTTT”” forfor thethe statestate code,code, thethe TribalTribal CodeCode forfor thethe countycounty andand thethe sitesite id.id. OtherwiseOtherwise useuse thethe StateState Code,Code, CountyCounty CodeCode andand SiteSite IDID

SELECT DECODE(ta_tribal_code, NULL, cn_stt_state_code, ‘TT’) || ‘-’ || NVL(ta_tribal_code, cc_cn_county_code) || ‘-’ || site_id “AIRS Site ID” FROM sites 45 OracleOracle DatesDates

„ DatesDates storedstored inin OracleOracle asas aa numbernumber „ January 1, 4712 BC – December 31, 4712 AD „ Use the TO_CHAR function to display the way you want it „ System default is usually DD-MON-YY Format „ Dates are stored down to the second „ ““SYSDATESYSDATE”” == RightRight nownow (down(down toto thethe second)second)

46 DateDate ComparisonsComparisons

„ IfIf youyou comparecompare twotwo datedate values,values, thethe valuesvalues mustmust matchmatch downdown toto thethe secondsecond „ TO_DATE(TO_DATE(‘‘2004111620041116’’,, ‘‘YYYYMMDDYYYYMMDD’’)) == sysdatesysdate isis notnot aa truetrue statement.statement. „ YouYou cancan performperform anyany arithmeticarithmetic comparisoncomparison betweenbetween 22 datesdates „ >> ,, << ,, =,=, !=,!=, BETWEENBETWEEN

47 DateDate FunctionsFunctions

„ YouYou cancan convertconvert aa stringstring toto aa datedate (TO_DATE)(TO_DATE) andand aa datedate toto aa stringstring (TO_CHAR)(TO_CHAR) „ TO_DATE(‘2004-NOV-02’, ‘YYYY-MON-DD’) „ TO_CHAR(sysdate, ‘YYYYMMDD’) „ YouYou cancan truncatetruncate aa datedate (TRUNC)(TRUNC) toto makemake comparisonscomparisons easiereasier „ TRUNC(SYSDATE) = Midnight of today’s date „ TRUNC(SYSDATE, ‘YYYY’) = January 1 of the current year „ TRUNC(SYDATE, ‘MM’) = Day 1 of the current month

48 DateDate ComparisonComparison ExampleExample

„ SelectSelect thethe MO_IDsMO_IDs,, ReportingReporting AgencyAgency Codes,Codes, andand yearyear forfor monitorsmonitors thatthat reportedreported datadata

SELECT ans.mo_mo_id, ar.sa_ag_agency_code, ans.annual_summary_year year FROM annual_summaries ans, agency_roles ar WHERE ans.mo_mo_id = ar.mo_mo_id AND ar.rol_role = ‘REPORTING’ AND TO_DATE(ans.annual_summary_year|| ‘0101’, ‘YYYYMMDD’) BETWEEN TRUNC(ar.agency_role_begin_date, ‘YYYY’) AND NVL(ar.agency_role_end_date, sysdate)

49 DateDate ArithmeticArithmetic

„ IfIf youyou subtractsubtract oneone datedate fromfrom anotheranother youyou getget thethe numbernumber ofof daysdays betweenbetween thethe twotwo datesdates „ IfIf youyou addadd oror subtractsubtract aa numbernumber toto aa datedate youyou getget aa datedate thatthat manymany daysdays inin thethe futurefuture (+)(+) oror pastpast ((--))

50 MoreMore DateDate FunctionsFunctions

„ ADD_MONTHSADD_MONTHS –– MoveMove aa datedate xx monthsmonths intointo thethe futurefuture „ LAST_DAYLAST_DAY –– ReturnsReturns thethe datedate thatthat isis thethe lastlast dayday ofof thethe monthmonth forfor thethe suppliedsupplied monthmonth „ MONTHS_BETWEENMONTHS_BETWEEN –– NumberNumber ofof monthsmonths betweenbetween 22 datesdates „ ROUNDROUND –– LikeLike TRUNC,TRUNC, butbut willwill givegive youyou thethe higherhigher formattedformatted valuevalue ifif moremore thanthan ½½ ofof thethe periodperiod hashas expiredexpired

51 DateDate ArithmeticArithmetic && FunctionFunction ExampleExample

„ Select the time right now (Hour, minute, second), the number of days since the first of the year, the number of days until the end of the year, the number of days until the end of the month, number of hours left in the day

SELECT TO_CHAR(sysdate, ‘HH24:MI:SS’) right_now, TRUNC(sysdate) – TRUNC(sysdate, ‘YYYY’) first_of_year, TRUNC(ADD_MONTHS(sysdate,12), ‘YYYY’) – TRUNC(sysdate) end_of_year, TRUNC(ADD_MONTHS(sysdate,1), ‘MON’) – TRUNC(sysdate) end_of_month, ROUND((TRUNC(sysdate+1) – sysdate) * 24) FROM DUAL

52 SummarySummary

„ FunctionsFunctions areare prepre--writtenwritten programsprograms thatthat maymay taketake variablesvariables andand returnsreturns aa valuevalue „ OracleOracle hashas severalseveral builtbuilt--inin functionsfunctions „ StringString „ MathMath „ DateDate „ TranslationTranslation „ FunctionsFunctions cancan bebe usedused inin combinationcombination

53 SummarySummary (Continued)(Continued)

„ AA functionfunction maymay havehave multiplemultiple meaningsmeanings basedbased onon thethe typetype ofof informationinformation providedprovided (TRUNC(TRUNC forfor example)example) „ OracleOracle DatesDates „ BeBe carefulcareful youyou knowknow whatwhat timetime youyou havehave „ DateDate arithmeticarithmetic „ DateDate functionsfunctions

54 AnyAny Questions?Questions?

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