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Oracle PL/SQL Programming: A Developer's Workbook
book

Oracle PL/SQL Programming: A Developer's Workbook

by Steven Feuerstein, Andrew Odewahn
May 2000
Intermediate to advanced content levelIntermediate to advanced
594 pages
11h 32m
English
O'Reilly Media, Inc.
Content preview from Oracle PL/SQL Programming: A Developer's Workbook

Expert

20-21.

How should the format mask be changed in this call to TO_CHAR so that all extra spaces and padded zeros are removed?

TO_CHAR (SYSDATE, 'Month DD, YYYY')

20-22.

What format mask element could you use to validate a date (i.e., raise an exception if a date uses a four-digit year)?

20-23.

The built-in TO_DATE function—just like the underlying database itself—can understand only one date format: either the default for the database instance or the “override” format provided in the call to TO_DATE. For example, if the default date mask is MM/DD/YYYY, these calls to TO_DATE work fine:

TO_DATE ('1/7/1999')
TO_DATE ('01-07-1999')
TO_DATE ('Jan-19-99', 'MON-DD-RR')

But these calls to TO_DATE raise errors:

TO_DATE ('Jan-19-99')
TO_DATE ('1999-1-1')

Write a replacement smarter version of TO_DATE; the function should accept a single string argument and, if it represents a supported date format, return a date. Your function should support (at minimum) the following date formats:

MM/DD
M/DD/YY
MM/DD/YYYY
DD-MON
MON DD, YYYY
MONTH DD, YYYY
DD-MON-YY
DD-MON-YYYY
MON-DD-YYYY

20-24.

Assume that the following data is in a table called a_bunch_of_numbers:

number_col1 number_col2
1            99
2            98
3            97
...           ...
100           0

Write a query to retrieve rows where the difference between the two columns is less than or equal to 25.

20-25.

Professor Twoplus Two needs a function to generate a specific set of numbers for his experiments. He has identified this requirement:

Given a number of length n, return a set of numbers with the last ...

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Publisher Resources

ISBN: 9781449324070Supplemental ContentErrata Page