Module 13 (Introduction to SQL - Part 2).pdf

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The DELETE VerbHere is a simple and dangerous DELETEstatement:DELETE * FROM OrdersOf course, if you’ve applied referential integritytechniques when designing the database, youprobably won’t able <strong>to</strong> get away with the abovecommand, since it has common key relationshipswith other tables and the delete won’t go forward.
The DELETE VerbHere is one that might make more sense:DELETE * FROM Orders WHERE OrderDateBetween #1-Jan-93# AND #31-Dec-93#In general, about the only time you want <strong>to</strong> deleteall records in a table is when you have been usinga temporary table as a scratchpad of some sort, orif you’ve already made an archival backup and cannow get rid of main data.
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Whirlwind Tour of SQL, Part 2Web an
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AGGREGATE FUNCTIONS
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Aggregate FunctionsConsider this co
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Aggregate FunctionsSince the name w
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Aggregate FunctionsIn general, you
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Aggregate FunctionsFunction UseAppl
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Aggregate FunctionsIf all we could
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Aggregate FunctionsYou do not have
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GroupingIn the first query, the sum
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GroupingIncidentally, the above is
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JOIN CLAUSES
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The JOIN ClauseJoins usually make u
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Design StrategiesThis is generally
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The JOIN ClauseThe join key or comm
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The JOIN ClauseThe above query will
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Speeding Things UpWe could have wri
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Relationships among TablesThe way w
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One-To-ManyOne-to-Many: The most li
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Showing RelationshipsIn the query w
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Showing RelationshipsNotice this re
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TYPES OF JOIN CLAUSES
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The INNER JOINThis is the default t
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The INNER JOINIn the above example,
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The LEFT JOINThe LEFT JOIN specifie
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The RIGHT JOINThe RIGHT JOIN specif
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The OUTER JOINThe OUTER or FULL JOI
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The OUTER JOINThis means possibly g
Page 55 and 56: The CROSS JOINThis is a very odd ty
Page 57 and 58: The CROSS JOINHowever, when running
Page 59 and 60: Using JOIN and WHEREOf course, we c
Page 61 and 62: Using JOIN and ORDER BYWe can also
Page 63 and 64: Using JOIN and WHEREHere, the sort
Page 65 and 66: Compound JoinsFinal ResultsResults
Page 67 and 68: Compound JoinsThis example produces
Page 69 and 70: Compound JoinsThe Sum(Ccur(...)) po
Page 71 and 72: Compound JOINsIn the JOIN section,
Page 73 and 74: The Self JOINThis is used to join a
Page 75 and 76: Non-Equi JOINsBut this will give us
Page 77 and 78: SubqueriesThis is a powerful techni
Page 79 and 80: SubqueriesThis example involves usi
Page 81 and 82: SubqueriesThe third example, involv
Page 83 and 84: SELECT … INTO StatementsEverythin
Page 85 and 86: SELECT … INTO StatementsThe list
Page 87 and 88: INSERT STATEMENTS
Page 89 and 90: The INSERT VerbThe easiest way to a
Page 91 and 92: The INSERT VerbWhere:• tablename
Page 93 and 94: INSERT ExampleEvery value given in
Page 95 and 96: INSERT ExampleAlso note that we nei
Page 97 and 98: The INSERT VerbBecause it is so use
Page 99 and 100: A Better ApproachOr… put the code
Page 101 and 102: Notes About INSERTThere are usually
Page 103 and 104: Notes about INSERTDEFAULT can be us
Page 105: The DELETE VerbThe DELETE verb is a
Page 109 and 110: The DELETE VerbOften, you should gi
Page 111 and 112: The UPDATE VerbThe UPDATE command a
Page 113 and 114: UPDATE ExampleThis one might make m
Page 115 and 116: UPDATE ExampleOf course this might
Page 117 and 118: SQL TransactionsA critically import
Page 119 and 120: SQL TransactionsIt would be disastr
Page 121 and 122: SQL TransactionsIn SQL, it might lo
Page 123 and 124: SQL TransactionsThe opposite of a C
Page 125 and 126: CONCLUSIONS
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