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Re: DAYNAME problem using CASE statement
Posted by: Peter Brawley
Date: May 07, 2020 08:34AM

That form of Case clause compares When subclause values with the value following the Case keyword, as you can see ...

set @x=5;
select @x, pow(@x,2),case @x when pow(@x,2)=25 then @x+2 else @x+1 end as xnew; 
+------+-----------+------+
| @x   | pow(@x,2) | xnew |
+------+-----------+------+
|    5 |        25 |    6 |
+------+-----------+------+

...ie pow(@x,2)=25 evaluates to 1 which<>@x. You need ...

set @d = '2020-5-9'; -- sat
SELECT
@d, DAYNAME(@d),
CASE @d WHEN DAYNAME(@d) = "Saturday" THEN DATE_ADD(@d, INTERVAL 2 DAY)
ELSE DATE_ADD(@d, INTERVAL 1 DAY) END as despatchDate;
+----------+-------------+--------------+
| @d | DAYNAME(@d) | despatchDate |
+----------+-------------+--------------+
| 2020-5-9 | Saturday | 2020-05-11 |
+----------+-------------+--------------+
[/code]

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Re: DAYNAME problem using CASE statement
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May 07, 2020 08:34AM


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