The following are number examples for the to_char function.
to_char(1210.73, '9999.9') would return '1210.7' to_char(1210.73, '9,999.99') would return '1,210.73' to_char(1210.73, '$9,999.00') would return '$1,210.73' to_char(21, '000099') would return '000021'
The following is a list of valid parameters when the to_char function is used to convert a date to a string. These parameters can be used in many combinations.
Parameter Explanation YEAR Year, spelled out YYYY 4-digit year YYY
YY
YLast 3, 2, or 1 digit(s) of year. IYY
IY
ILast 3, 2, or 1 digit(s) of ISO year. IYYY 4-digit year based on the ISO standard Q Quarter of year (1, 2, 3, 4; JAN-MAR = 1). MM Month (01-12; JAN = 01). MON Abbreviated name of month. MONTH Name of month, padded with blanks to length of 9 characters. RM Roman numeral month (I-XII; JAN = I). WW Week of year (1-53) where week 1 starts on the first day of the year and continues to the seventh day of the year. W Week of month (1-5) where week 1 starts on the first day of the month and ends on the seventh. IW Week of year (1-52 or 1-53) based on the ISO standard. D Day of week (1-7). DAY Name of day. DD Day of month (1-31). DDD Day of year (1-366). DY Abbreviated name of day. J Julian day; the number of days since January 1, 4712 BC. HH Hour of day (1-12). HH12 Hour of day (1-12). HH24 Hour of day (0-23). MI Minute (0-59). SS Second (0-59). SSSSS Seconds past midnight (0-86399). FF Fractional seconds.
The following are date examples for the to_char function.
to_char(sysdate, 'yyyy/mm/dd'); would return '2003/07/09' to_char(sysdate, 'Month DD, YYYY'); would return 'July 09, 2003' to_char(sysdate, 'FMMonth DD, YYYY'); would return 'July 9, 2003' to_char(sysdate, 'MON DDth, YYYY'); would return 'JUL 09TH, 2003' to_char(sysdate, 'FMMON DDth, YYYY'); would return 'JUL 9TH, 2003' to_char(sysdate, 'FMMon ddth, YYYY'); would return 'Jul 9th, 2003'
You will notice that in some examples, the format_mask parameter begins with "FM". This means that zeros and blanks are suppressed. This can be seen in the examples below.
to_char(sysdate, 'FMMonth DD, YYYY'); would return 'July 9, 2003' to_char(sysdate, 'FMMON DDth, YYYY'); would return 'JUL 9TH, 2003' to_char(sysdate, 'FMMon ddth, YYYY'); would return 'Jul 9th, 2003'
The zeros have been suppressed so that the day component shows as "9" as opposed to "09".
Oracle函數to_char轉化數字型指定小數點位數的用法
to_char,函數功能,就是將數值型或者日期型轉化為字符型。
比如最簡單的應用:
Select TO_CHAR(1.0123) FROM DUAL
/*123--->'123'*/
Select TO_CHAR(123) FROM DUAL
接下來再看看下面:
SELEC TO_CHAR(0.123) FROM DUAL
上面的結果 '.123' 在大多數情況下都不是我們想要的結果,我們想要的應該是 '0.123'。
我們來看一下to_char函數的具體用法:
TO_CHAR ( n [, fmt [, 'nlsparam']] )
.小數點字符
.組分隔符
.本地錢幣符號
.國際錢幣符號
變元的形式為:
'NLS_NUMERIC_CHARACTERS="dg" NLS_CURRENCY="tcxt" NLS_ISO_CURRENCY=territory'
其中d為小數點字符,g為組分隔符。
例 :TO_CHAR (17145,'L099G999','NLS_NUMERIC_CHARACTERS=".," NLS_CURRENCY="NUD"')=NUD017,145
通過上面的了解,再查看fmt的一些格式,我們可以用以下表達式得到'0.123'的值:
Select TO_CHAR(0.123,'0.999') FROM DUAL
/*100.12 ---> '######' */
Select TO_CHAR(100.12,'0.999') FROM DUAL
/*1.12 ---> ' 1.120' */
Select TO_CHAR(1.12,'0.999') FROM DUAL
' 0.123'是出來了,可是前面又多了一個空格。
對於 100.12 的值卻是######,以及'1.12'的值變成了 '1.120'。
我們重新確定一個新的需求:
1、去空格
2、小數點最多4位,最少保留2位。
1--->'1.00';1.1--->'1.00';1.12-->'1.12';1.1234--->'1.1234';
1.12345--->'1.1235'
最終實現如下:
FM :除空格
9999999.0099:允許小數點左邊最大正數為7位,小數點右邊最少2位,最多4位,且在第5位進行四舍五入
*/
Select TO_CHAR(123.0233,'FM9999999.0099') FROM DUAL
to_char函數特殊用法
to_char(sysdate,'d') 每周第幾天
to_char(sysdate,'dd') 每月第幾天
to_char(sysdate,'ddd') 每年第幾天
to_char(sysdate,'ww') 每年第幾周
to_char(sysdate,'mm') 每年第幾月
to_char(sysdate,'q') 每年第幾季
to_char(sysdate,'yyyy') 年
比如要找某個時間為每周第幾天就可以
SQL> select to_char(to_date('20070101','yyyymmdd'),'d') from dual;
轉載至:http://blog.csdn.net/aqszhuaihuai/article/details/4051401