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nvl( ) º¯Êý
ʾÀý Çë²ÎÔÄ
´ÓÁ½¸ö±í´ïʽ·µ»ØÒ»¸ö·Ç null Öµ¡£
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NVL(eExpression1, eExpression2)
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eExpression1, eExpression2
Èç¹û eExpression1 µÄ¼ÆËã½á¹ûΪ null Öµ£¬Ôò NVL( ) ·µ»Ø eExpression2¡£Èç¹û eExpression1 µÄ¼ÆËã½á¹û²»ÊÇ null Öµ£¬Ôò·µ»Ø eExpression1¡£eExpression1 ºÍ eExpression2 ¿ÉÒÔÊÇÈÎÒâÒ»ÖÖÊý¾ÝÀàÐÍ¡£Èç¹û eExpression1 Óë eExpression2 µÄ½á¹û½ÔΪ null Öµ£¬Ôò NVL( ) ·µ»Ø .NULL.¡£
·µ»ØÖµÀàÐÍ
×Ö·ûÐÍ¡¢ÈÕÆÚÐÍ¡¢ÈÕÆÚʱ¼äÐÍ¡¢ÊýÖµÐÍ¡¢»õ±ÒÐÍ¡¢Âß¼­ÐÍ»ò null Öµ
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ÔÚ²»Ö§³Ö null Öµ»ò null ÖµÎ޹ؽôÒªµÄÇé¿öÏ£¬¿ÉÒÔʹÓà NVL( ) À´ÒÆÈ¥¼ÆËã»ò²Ù×÷ÖÐµÄ null Öµ¡£
select nvl(a.name,'¿ÕµÃ') as name from student a join school b on a.ID=b.ID
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isNaN º¯Êý
isNaN(expression:Object) : Boolean
¼ÆËã²ÎÊý£¬Èç¹ûֵΪ NaN£¨·ÇÊý×Ö£©£¬Ôò·µ»Ø true¡£´Ëº¯Êý¿ÉÓÃÓÚ¼ì²éÒ»¸öÊýѧ±í´ïʽÊÇ·ñ³É¹¦µØ¼ÆËãΪһ¸öÊý×Ö¡£
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function checknum()
{
if ( isNaN (frm.num.value))
{
alert("ÇëÊäÈëÊý×Ö");
frm.num.focus();
}
 
 lpad º¯Êý
ÔÚ Oracle /PLSQLÖÐ, lpad º¯Êý½«×ó±ßµÄ×Ö·û´®Ìî³äÒ»Ð©ÌØ¶¨µÄ×Ö·û,
ÆäÓï·¨¸ñʽÈçÏ£º    
  lpad ( string1, padded_length, [ pad_string ] )
×÷Ó㺰ÑaddStringÌí¼Óµ½aµÄ×ó±ß£¬length ÊÇ·µ»ØÖµµÄ³¤¶È
3Àý×Ó
                  A £º SQL> select lpad ('test',8,0) from dual;
                LPAD ('TEST',8,0)
                    ----------------
                 0000test
               B£º select lpad ('test',8) from dual;
              LPAD ('TEST',8)
         


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Oracle ´¥·¢Æ÷

 
create table emp2_log(
 uname varchar2(20),
 action varchar(10),
 atime date
);
create or replace trigger trig
   after insert or delete or update on emp2 for each row  //°óÔÚÒ»ÕűíÉÏ,before after ¶¼¿É
ÒÔ,beforeÊÇ ²åÊý¾Ý֮ǰ£¬afterÊÇÖ®ºó
begin
 &nb ......

¡°ÓÅÐãʾÀý¡±: Oracle´úÂë¹æ³Ì

 ÔÚPL/SQLÖÐʹÓÃÕóÁд¦ÀíÊÇÒ»¸öºÜºÃµÄ×ö·¨(È磬ʹÓÃbulk collectºÍforall)¡£ÅúÁ¿´¦ÀíÄܹ»´ó´ó¼õÉÙPL/SQLÓï¾äÖ´ÐÐÒýÇæµÄ»·¾³Çл»´ÎÊý£¬´Ó¶øÌá¸ßÆäÐÔÄÜ¡£
¡¡¡¡ÁíÒ»¸öÓÅÐãʾÀýÊǰѴ洢¹ý³ÌÖеÄËùÓдúÂë·ÅÈëËø¶¨µÄÈí¼þ°üÖУ¬ÕâÑù¿ÉÒÔÉú³ÉÄ£¿éµ¥Ôª¡£°Ñ´æ´¢¹ý³Ì·ÅÈëÈí¼þ°üÀï¿ÉÒÔʵÏÖÏà¹Ø³ÌÐòºÍ¹¦ÄܵķÖ×é¡£µ±
µ¥¸ö°ü±»Ê¹Óà ......

Virtual Columns in Oracle Database 11g

When queried, virtual columns appear to be normal table columns, but
their values are derived rather than being stored on disc. The syntax
for defining a virtual column is listed below.
column_name [datatype] [GENERATED ALWAYS] AS (expression) [VIRTUAL]
If the datatype is omitted, it is determin ......

ORACLE PL/SQL ´æ´¢¹ý³Ì½Ì³Ì


(1)SEQNAME.NEXTVALÀïÃæµÄÖµÈçºÎ¶Á³öÀ´£¿¿ÉÒÔÖ±½ÓÔÚinsert into test values(SEQNAME.NEXTVAL) ÊÇ¿ÉÒÔÓà  ÕâÑù£º     
SELECT tmp#_seq.NEXTVAL
        INTO id_temp
        from DUAL;  È»ºó¿ÉÒ ......

java²Ù×÷oracleÊý¾Ý¿â

 package com.chinacache.boss.queryservice.service.impl;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import com.chinacache.boss.queryservice.excepti ......
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