oracle nvl decode
SELECT
DECODE(ÁÐ,0,'Q'1,'P',2,'O')¡¡AS ret
from dual
--·ÖÎö: µ± ÁÐ=0ʱ,½«"Q"¸³Öµ
--µ± ÁÐ =1ʱ,½«"P"¸³Öµ
--µ± ÁÐ=2ʱ,½«"O"¸³Öµ
--NVL()º¯Êý:
--NVL(ARG,VALUE)´ï±êÈç¹ûÇ°ÃæµÄARGֵΪNULLÄÇô·µ»ØµÄֵΪºóÃæµÄVALUE¶þÕß½áºÏʹÓÃ:
DECODE(NVL(±äÁ¿ ''),'','-','OK')
//·ÖÎö:
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--Æä´Î,ÅжÏÈ¡³öµÄ×Ö¶ÎÊÇ·ñΪ¿Õ,Èç¹ûÊÇÔò¸³¸ø'-'
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