The Easiest Introduction to SQL, with Useful Tasks Explained From Scratch Covers Everything From How to Manipulate Values, & Tables Queries, to Handling Implied Range & Variables Correlated Subqueries . . So f>t£/** Su'S SELECT Command The SELECT * I { [ DISTINCTI ALL] <value expression> .,. . } FROM {<tablename> [<a//as>]} .,. WHERE <predicate>] [ GROUP BY <column name> <integer> }.,..] [ { I HAVING <predicate>) [ ORDER BY <column name> <integer> }.,..] [ { I UNION [ALL] [ { SELECT * [DISTINCT ALL] <value expression> I { I . , . . } FROM {<table name> [<a//as>]} .,.. WHERE <predicate> [ GROUP BY Kcolumn name> <integer> }.,..] [ { I HAVING <predicate>] [ ORDER BY Kcolumn name> <integer> }[ ]; { I } . ,. .] The Elements Used in the SELECT Command Element Definition <valueexpression> An expression that produces a value. It may include or consist ofa <column name^ <table names' A name ofor synonym for a table or view. <.alias's* A temporary synonym for <Ctable name~> defined here and , usable only in this command. <predicated A condition that can be true or false for each row or FROM combination ofrows from the table(s) in the clause. ^.column names* A name ofa column ofthe table. <.integers' A number with no decimal point. In this case, it indicates a <valueexpression^ in the SELECT clause by identifying its placement in that clause. > . The Update Commands UPDATE UPDATE <table name> SWETHE{RIE} .<,p.r.e<dcioclautem>n name> = <value expression> [ WHERE CURRENT OF <cursorname I ('embedded only*) ]; INSERT INSERT INTO Ktable name> (<column name> .,..)] [ { VALUES ( <value expression> .,. . ) } <query>; I DELETE DELETE FROM <table name> WHERE <predicate> [ WHERE CURRENT OF <cursorname> I ('embedded only*) ]; The Elements Used in the Update Commands Element Definition <cursor name> Name ofa cursor used in this program. <query> A valid SELECT command. For other elements, see the SELECT command. The Symbols Used in Syntax Statements Symbol Explanation Whatever precedes this symbol may optionally be replaced by whatever 1 follows it. This is a symbolic way ofsaying "or". {} Everythingenclosed in curly brackets is treated as a unit for the purposes ofevaluating or other symbols. 1 , . , . . [] Everything enclosed in square brackets is optional. Whatever precedes this may be repeated any number oftimes. . , . Whatever precedes this may be repeated any number oftimes with the individual occurrences separated by commas. SQL Understanding SQL Understanding MARTIN GRUBER SYBEX San Francisco Paris Diisseldorf Soest AcquisitionsEditor: DianneKing Editors: MichaelL.Wolk,EricStone, LynCordell TechnicalEditor:JonForrest WordProcessors:ScottCampbell.DeborahMaizels BookDesigner:JulieBilski ChapterArtandLayout:CharlotteCarter ScreenGraphics:DeliaBrown Typesetter:TheTypesettingShop, Inc. Proofreader: EdLin CoverDesigner:ThomasIngalls + Associates CoverPhotographer: MichaelLamotte ScreenreproductionsproducedbyXenoFont ORACLEisatrademarkofOracleCo. IBMandDB2aretrademarksofInternationalBusinessMachinesCorporation. FirstSQLisatrademarkofFFESoftware. XenoFontisatrademarkofXenoSoft. SYBEXisaregisteredtrademarkofSYBEX, Inc. TRADEMARKS: SYBEXhasattemptedthroughoutthisbooktodistinguishproprietary trademarksfromdescriptivetermsbyfollowingthecapitalizationstyleusedbythemanufacturer. SYBEXisnotaffiliatedwithanymanufacturer. Everyefforthasbeenmadetosupplycompleteandaccurateinformation. However, SYBEX assumesnoresponsibilityforitsuse, norforanyinfringementoftheintellectualpropertyrightsof thirdpartieswhichwouldresultfromsuchuse. Copyright©1990SYBEXInc.,2021ChallengerDrive#100,Alameda,CA94501.Worldrights reserved. Nopartofthispublicationmaybestoredinaretrievalsystem,transmitted,orreproduced inanyway,includingbutnotlimitedtophotocopy,photograph,magneticorotherrecord,without theprioragreementandwrittenpermissionofthepublisher. LibraryofCongressCardNumber:89-51772 ISBN0-89588-644-8 ManufacturedintheUnitedStatesofAmerica 10 9 8 7 A his book is dedicated to Lee andJanet Fesperman for getting me involved in this whole thing in the first place.