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Concept visual
Start at both ends
Go through conditions and return a value when the first condition is met: SELECT OrderID, Quantity,
Formula
WHEN Quantity > 30
THEN "The quantity is greater than 30"
WHEN Quantity =30 THEN "The quantity is 30" ELSE "The quantity is under 30"
FROM OrderDetails;The CASE statement goes through conditions and return a value when the first condition is met (like an IF-THEN-ELSE statement). So, once a condition is true, it will stop reading and return the result.
If no conditions are true, it will return the value in the ELSE clause.If there is no ELSE part and no conditions are true, it returns NULL.
condition1
result1
condition2
result2
conditionN
resultN
result
END;Description condition1, condition2, ...conditionN Required. The conditions. These are evaluated in the same order as they are listed result1, result2, ...resultN
Required. The value to return once a condition is trueFrom MySQL 4.0
The following SQL will order the customers by City. However, if City is NULL, then order by Country:
SELECT CustomerName, City, Country
(CASE
END);❮ MySQL Functions