Parameter Explanation YEAR Year, spelled out YYYY 4-digit year YYY YY Y Last 3, 2, or 1 digit(s) of year. IYY IY I Last 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(简化的,缩写的,简缩的 2.简短的) 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. 少的 4.微小 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' Fractional 1.部分的，碎片的 fractional 1.分级的 2.分数的 3.极小,极
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. 隐瞒 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". suppress 1.镇压, 抑制, 查禁, 使止住 2.镇压；抑制；隐瞒 3.禁止披露；
十一： 十一：Oracle 中 TO_DATE TO_CHAR 格式 TO_NUMBER
2009-04-23 18:02:21
TO_CHAR 是把日期或数字转换为字符串 TO_DATE 是把字符串转换为数据库中得日期类型转换函数 TO_NUMBER 将字符转化为数字
″ TO_CHAR 使用 TO_CHAR 函数处理数字 TO_CHAR(number, '格式') TO_CHAR(salary,’$99,999.99’); 使用 TO_CHAR 函数处理日期 TO_CHAR(date,’格式’);
″ TO_NUMBER
使用 TO_NUMBER 函数将字符转换为数字 TO_NUMBER(char[, '格式'])
″ TO_DATE 使用 TO_DATE 函数将字符转换为日期 TO_DATE(char[, '格式'])
″ 数字格式格式 9 代表一个数字 0 强制显示 0 $ 放置一个$符 L 放置一个浮动本地货币符 . 显示小数点 , 显示千位指示符
″ 日期格式 格式控制 描述 YYYY、YYY、YY 分别代表 4 位、
