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sqlÓïÑÔÖÐÓÐûÓÐÀàËÆCÓïÑÔÖеÄswitch caseµÄÓï¾ä£¿£¿
ûÓÐ,ÓÃcase when À´´úÌæ¾ÍÐÐÁË.
ÀýÈç,ÏÂÃæµÄÓï¾äÏÔʾÖÐÎÄÄêÔÂ
select getdate() as ÈÕÆÚ,case month(getdate())
when 11 then 'ʮһ'
when 12 then 'Ê®¶þ'
else substring('Ò»¶þÈýËÄÎåÁùÆß°Ë¾ÅÊ®', month(getdate()),1)
end+'ÔÂ' as Ô·Ý
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SELECT <myColumnSpec> =
CASE
WHEN <A> THEN <somethingA>
WHEN <B> THEN <somethingB>
ELSE <somethingE>
END
ÔÚÉÏÃæµÄ´úÂëÖÐÐèÒªÓþßÌåµÄ²ÎÊý´úÌæ¼âÀ¨ºÅÖеÄÄÚÈÝ¡£ÏÂÃæÊÇÒ»¸ö¼òµ¥µÄÀý×Ó£º
USE pubs
GO
SELECT
Title,
'Price Range' =
CASE
WHEN price IS NULL THEN 'Unpriced'
WHEN price < 10 THEN 'Bargain'
WHEN price BETWEEN 10 and 20 THEN 'Average'
ELSE 'Gift to impress relatives'
END
from titles
ORDER BY price
GO
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SELECT 'Number of Titles', Count(*)
from titles
GROUP BY
CASE
WHEN price IS NULL THEN 'Unpriced'
&n
Ïà¹ØÎĵµ£º
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