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

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The JOIN ClauseTo retrieve joined data from two or more tables,the tables must first share a meaningfulrelationship. The tables to be joined must possessa column or columns that share a common set ofvalues that allow the tables to be meaningfullinked.The common column(s) are called the join key orcommon key.
The JOIN ClauseThe join key or common key will often be thenatural key of the tables involved.For example, the field EmployeeID in thesituation where we join Employees withEmployeeTraining.It is highly unusual for there to be more than onekey that can tie together a given pair of tables. Ifyou are seeing that in your design, you areprobably doing something wrong.
Page 1 and 2: Whirlwind Tour of SQL, Part 2Web an
Page 3 and 4: AGGREGATE FUNCTIONS
Page 5 and 6: Aggregate FunctionsConsider this co
Page 7 and 8: Aggregate FunctionsSince the name w
Page 9 and 10: Aggregate FunctionsIn general, you
Page 11 and 12: Aggregate FunctionsFunction UseAppl
Page 13 and 14: Aggregate FunctionsIf all we could
Page 15 and 16: Aggregate FunctionsYou do not have
Page 17 and 18: GroupingIn the first query, the sum
Page 19 and 20: GroupingIncidentally, the above is
Page 21 and 22: JOIN CLAUSES
Page 23 and 24: The JOIN ClauseJoins usually make u
Page 25: Design StrategiesThis is generally
Page 29 and 30: The JOIN ClauseThe above query will
Page 31 and 32: Speeding Things UpWe could have wri
Page 33 and 34: Relationships among TablesThe way w
Page 35 and 36: One-To-ManyOne-to-Many: The most li
Page 37 and 38: Showing RelationshipsIn the query w
Page 39 and 40: Showing RelationshipsNotice this re
Page 41 and 42: TYPES OF JOIN CLAUSES
Page 43 and 44: The INNER JOINThis is the default t
Page 45 and 46: The INNER JOINIn the above example,
Page 47 and 48: The LEFT JOINThe LEFT JOIN specifie
Page 49 and 50: The RIGHT JOINThe RIGHT JOIN specif
Page 51 and 52: The OUTER JOINThe OUTER or FULL JOI
Page 53 and 54: 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
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SELECT … INTO StatementsThe list
Page 87 and 88:
INSERT STATEMENTS
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The INSERT VerbThe easiest way to a
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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
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Notes about INSERTDEFAULT can be us
Page 105 and 106:
The DELETE VerbThe DELETE verb is a
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The DELETE VerbHere is one that mig
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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
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UPDATE ExampleOf course this might
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SQL TransactionsA critically import
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SQL TransactionsIt would be disastr
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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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