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Self Joins - Intro to Relational Databases

  • 0:00 - 0:04
    When you ran this query,
    what was it that wasn't right about it?
  • 0:04 - 0:06
    Well, it seems to think
    that each student is his or
  • 0:06 - 0:12
    her own roommate, and it lists each pair
    of roommates twice in alternating order.
  • 0:12 - 0:16
    There are a lot of ways to fix this,
    but here's just one of them.
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    By asking only for the rows where
    this id, is less than that id.
  • 0:21 - 0:25
    We eliminate the rows where they're
    equal, in other words the same student.
  • 0:25 - 0:28
    And, we eliminate one out
    of each pair of duplicates.
Title:
Self Joins - Intro to Relational Databases
Description:

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Video Language:
English
Team:
Udacity
Project:
ud197 - Intro to RDB
Duration:
0:29
Udacity Robot edited English subtitles for 04-15 Self Joins
Udacity Robot edited English subtitles for 04-15 Self Joins
Cogi-Admin edited English subtitles for 04-15 Self Joins

English subtitles

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