Video:
Design Pattern for Finding Duplicate Data - A Simple Way to Spot Non-Unique Rows (Multi Column Test)
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Skill level:
300 (Intermediate)
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Run Time:
13:02
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Instructor:
Scott Whigham
Description:
We have multiple SQL tutorials for writing queries to return duplicate data in a column or multiple columns. This video focuses on spotting dupes across multiple columns. Although primary keys prevent duplicate rows, having a Primary Key on "EmployeeId" does not prevent users from entering duplicate LastName/FirstName combinations. This video shows you how to use subqueries (both correlated and simple) along with EXISTS to locate non-unique rows.
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Scott Whigham
Scott Whigham is the founder of LearnItFirst.com, one of the web's most extensive
video training libraries focusing on technical training. Scott is also an experienced
consultant, trainer, and author with more than a decade of hands-on experience working
with SQL Server databases, writing and debugging applications using Visual Studio,
and performance tuning. Scott designed the architecture (websites, class libraries,
and database) for the LearnItFirst.com websites and, most
re...
(Scott's full bio can be found here)
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NOTE: This video is part of our
SQL Server Programming (SQL Server 2005/2000): Transact SQL course.
This video is from Chapter
16:
Design Patterns for Transact-SQL
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