发表于 2009-1-5 19:48
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oracle sql璇彞鐨凬ULL澶勭悊
鍙戝竷: 2008-6-30 22:35 | 浣滆: admin | 鏌ョ湅: 18娆
oracle sql璇彞鐨凬ULL澶勭悊
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銆愬瓧浣擄細灏 澶с
oracle sql璇彞鐨凬ULL澶勭悊
浣滆咃細fengyun 鏂囩珷鏉ユ簮锛氭湰绔欏師鍒 鐐瑰嚮鏁帮細810 鏇存柊鏃堕棿锛2007-9-4 
Oracle 娌℃湁isnull()鍑芥暟锛屽拰浠栧姛鑳戒竴鏍风殑鍑芥暟鏄疦VL
琛ㄨ揪寮忔槸杩欐牱鐨勶細
NVL(Expr1,Expr2)濡傛灉Expr1涓篘ULL锛岃繑鍥濫xpr2鐨勫硷紝鍚﹀垯杩斿洖Expr1鐨勫
NVL2(Expr1,Expr2,Expr3)濡傛灉Expr1涓篘ULL锛岃繑鍥濫xpr2鐨勫硷紝鍚﹀垯杩斿洖Expr3鐨勫
NULLIF(Expr1,Expr2)濡傛灉Expr1鍜孍xpr2鐨勫肩浉绛夛紝杩斿洖NULL锛屽惁鍒欒繑鍥濫xpr1鐨勫
褰撳垽鏂袱涓兼槸鍚︾浉绛夌殑鏃跺欙紝濡傛灉鍏朵腑涓涓槸NULL锛屽垯杩欎釜琛ㄨ揪寮忚繑鍥瀗ull
鎵浠ヤ竴鑸兘杩涜鍒ゆ柇鏄笉鏄┖锛岀劧鍚庡湪姣旇緝.
