Case Expression vs. Case Statement: Understanding the Differences
In MySQL, Case Expression and Case Statement provide conditional logic for different scenarios. Let's explore their differences:
Evaluation and Usage:
Syntax:
Both constructs have similar syntax but with slight variations:
Case Expression:
CASE WHEN [condition] THEN result [WHEN [condition] THEN result ...] [ELSE result] END
Case Statement:
CASE WHEN search_condition THEN statement_list [WHEN search_condition THEN statement_list] ... [ELSE statement_list] END CASE
Usage in Stored Programs:
Case Statement is primarily intended for use within stored programs, where control flow and statement execution are required. However, Case Expression can also be used within stored programs if it is necessary to evaluate a condition and return a value.
Conclusion:
While both Case Expression and Case Statement perform conditional logic operations, their primary differences lie in their evaluation and usage characteristics. Case Expression is used for value evaluation, whereas Case Statement is used for statement execution. The syntax variations and usage restrictions in stored programs should be considered when selecting the appropriate construct.
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