A few days back while I was solving a problem at LeetCode, came across this problem Swap Salary. The problem was interesting when I have written an if-else condition like I do while coding. I never came across this type of interesting MySQL problem neither I had any work scenarios where I could have used such conditions. While browsing different websites and going through different resources I realized I should just write a blog on it, hope it helps everyone.
Case() is used to write conditions in the query with the if-else statement.
- When a condition is true, it will stop reading and will return the result
- If no conditions are true, it returns the value in the ELSE clause
- If there is no ELSE part and no conditions are true, it will return a NULL
CASE
WHEN condition1 THEN result1
WHEN condition2 THEN result2
WHEN conditionN THEN resultN
ELSE result
END;The problem in LeetCode asks for a solution where you need to swap the gender from m=f or vice versa. The solution is to write an update query with the case ().
update salary set sex = (case when sex = 'm' then 'f' else 'm' end);
Happy learning 💻💻
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