文件名称：日期函数-SQL语言基础
文件大小：5.26MB
文件格式：PPT
更新时间：2024-05-15 13:24:54
SQL 基础
日期函数 * 两个日期之间的月数 MONTHS_BETWEEN ADD_MONTHS NEXT_DAY LAST_DAY ROUND TRUNC 为一个日期增加月份 一个日期的下一个指定日子 （例如：星期1）的日期 某个月份的最后一天 对日期进行四舍五入计算 对日期进行取整计算 函数 描述 * Date Functions Date functions operate on Oracle dates. All date functions return a value of DATE datatype except MONTHS_BETWEEN, which returns a numeric value. MONTHS_BETWEEN(date1, date2): Finds the number of months between date1 and date2. The result can be positive or negative. If date1 is later than date2, the result is positive; if date1 is earlier than date2, the result is negative. The noninteger part of the result represents a portion of the month. ADD_MONTHS(date, n): Adds n number of calendar months to date. The value of n must be an integer and can be negative. NEXT_DAY(date, 'char'): Finds the date of the next specified day of the week ('char') following date. The value of char may be a number representing a day or a character string. LAST_DAY(date): Finds the date of the last day of the month that contains date. ROUND(date[,'fmt']): Returns date rounded to the unit specified by the format model fmt. If the format model fmt is omitted, date is rounded to the nearest day. TRUNC(date[, 'fmt']): Returns date with the time portion of the day truncated to the unit specified by the format model fmt. If the format model fmt is omitted, date is truncated to the nearest day. This list is a subset of the available date functions. The format models are covered later in this lesson. Examples of format models are month and year.