NVL (expr1, expr2)->expr1為NULL，返回expr2；不為NULL，返回expr1。註意兩者的類型要一致
NVL2 (expr1, expr2, expr3) ->expr1不為NULL，返回expr2；為NULL，返回expr3。expr2和expr3類型不同的話，expr3會轉換為expr2的類型
NULLIF (expr1, expr2) ->相等返回NULL，不等返回expr1
- Sep 04 Wed 2013 10:36
-
NVL , NVL2 ,COALESCE ,DECODE用法
NVL (expr1, expr2)->expr1為NULL，返回expr2；不為NULL，返回expr1。註意兩者的類型要一致
NVL2 (expr1, expr2, expr3) ->expr1不為NULL，返回expr2；為NULL，返回expr3。expr2和expr3類型不同的話，expr3會轉換為expr2的類型
NULLIF (expr1, expr2) ->相等返回NULL，不等返回expr1
- Sep 03 Tue 2013 09:37
-
Oracle INTERVAL的用法
select TO_CHAR(SYSDATE - INTERVAL '3' YEAR, 'YYYYMMDDHH24') ToYEAR, --=>從系統日期算起往前 3 年
TO_CHAR(SYSDATE - INTERVAL '3' month, 'YYYYMMDDHH24') ToMONTH, --=>從系統日期算起往前 3 個月
TO_CHAR(SYSDATE - INTERVAL '30' DAY, 'YYYYMMDDHH24') ToDay, --=>從系統日期算起往前 30 天
TO_CHAR(SYSDATE - INTERVAL '30' HOUR, 'YYYYMMDDHH24') ToHOUR,--=>從系統日期算起往前 30 小時
TO_CHAR(SYSDATE - INTERVAL '30' minute, 'YYYYMMDD HH24:MI:SS') ToMinute,--=>從系統日期算起往前 30 分鍾
TO_CHAR(SYSDATE - INTERVAL '50' second,'YYYYMMDD HH24:MI:SS') ToSecond,--=>從系統日期算起往前 50 秒
SYSDATE --系統日期
from dual
TO_CHAR(SYSDATE - INTERVAL '3' month, 'YYYYMMDDHH24') ToMONTH, --=>從系統日期算起往前 3 個月
TO_CHAR(SYSDATE - INTERVAL '30' DAY, 'YYYYMMDDHH24') ToDay, --=>從系統日期算起往前 30 天
TO_CHAR(SYSDATE - INTERVAL '30' HOUR, 'YYYYMMDDHH24') ToHOUR,--=>從系統日期算起往前 30 小時
TO_CHAR(SYSDATE - INTERVAL '30' minute, 'YYYYMMDD HH24:MI:SS') ToMinute,--=>從系統日期算起往前 30 分鍾
TO_CHAR(SYSDATE - INTERVAL '50' second,'YYYYMMDD HH24:MI:SS') ToSecond,--=>從系統日期算起往前 50 秒
SYSDATE --系統日期
from dual
- Aug 23 Fri 2013 10:14
-
如何確認MS-SQL是否成功備份?
Full Database Backups
FROM msdb.dbo.backupset
WHERE backup_start_date BETWEEN DATEADD(hh, -24, GETDATE()) AND GETDATE()
AND Type = 'D'
ORDER BY backup_set_id DESC
GO
Transaction Log Backups
FROM msdb.dbo.backupset
WHERE backup_start_date BETWEEN DATEADD(hh, -24, GETDATE()) AND GETDATE()
AND Type = 'L'
ORDER BY backup_set_id DESC
GO
Differential Backups
FROM msdb.dbo.backupset
WHERE backup_start_date BETWEEN DATEADD(hh, -24, GETDATE()) AND GETDATE()
AND Type = 'I'
ORDER BY backup_set_id DESC
GO
File\File Group Backups
FROM msdb.dbo.backupset
WHERE backup_start_date BETWEEN DATEADD(hh, -24, GETDATE()) AND GETDATE()
AND Type = 'F'
ORDER BY backup_set_id DESC
GO
- Aug 23 Fri 2013 10:04
-
Hash Map With iterator
import java.util.*;
public class HashMapDemo {
public static void main(String[] args) {
HashMap hm = new HashMap();
hm.put("Rohit", new Double(3434.34));
hm.put("Mohit", new Double(123.22));
hm.put("Ashish", new Double(1200.34));
hm.put("Khariwal", new Double(99.34));
hm.put("Pankaj", new Double(-19.34));
Set set = hm.entrySet();
Iterator i = set.iterator();
while(i.hasNext()){
Map.Entry me = (Map.Entry)i.next();
System.out.println(me.getKey() + " : " + me.getValue() );
}
//deposit into Rohit's Account
double balance = ((Double)hm.get("Rohit")).doubleValue();
hm.put("Rohit", new Double(balance + 1000));
System.out.println("Rohit new balance : " + hm.get("Rohit"));
}
}
1
