"SQL Advanced Course"

 

 

 

 

example:

 

 

 

 

 

 

 

 

 

 

 

 

 

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Note that the last must be written on the ELSE statement.

CASE expression introduced at the beginning of time we have learned, if not specified expressions CASE ELSE clause, the results will be processed into default ELSE NULL. Now I know the reason I want to emphasize the very beginning ELSE clause habitually written on it when using the CASE expression?

 

 

 

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 Exercises:

 

 

 

 

 

 

 

 

 

 

 

 

 

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 Deduplication:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                                                   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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