我想把这个参数换成trunc(sysdate,'dd') + ((ceil(to_char(sysdate,'sssss')/300) -1 ) / 288+2/(24*60))和这个等价的
时间: 2024-09-07 10:01:36 浏览: 82
这个表达式看起来是在Oracle数据库中计算当前日期的特定偏移量,用于得到一天的开始时间加上基于秒的复杂调整。`sysdate`获取当前系统日期,`trunc`函数截断到天,`ceil`向上取整,`to_char`转换为字符串然后除以300得到小时数的小数部分,再除以288(一天的分钟数)并减去1,之后除以24乘以60得到分钟。最后加两个额外的调整值。
简单来说,它的工作原理可以概括为:
1. 获取一天的开始时间(trunc(sysdate, 'dd'))
2. 计算出从00:00:00到当前时间的分钟偏移,并转化为天数的小数部分(调整后的小时数/288)
3. 加上两个额外的调整值
等价的SQL查询可能是这样的:
```sql
SELECT trunc(sysdate, 'dd') + ((
floor((sysdate - trunc(sysdate, 'dd')) * 288)
+ (CASE WHEN mod(floor((sysdate - trunc(sysdate, 'dd')) * 288), 288) < 300 THEN 1 ELSE 0 END)
+ (2 / (24 * 60))
) as adjusted_date
```
这里假设`mod`是余数运算符,`floor`向下取整。
相关问题
SELECT (SYSDATE-TRUNC(SYSDATE))*24 NOWDATE,TO_CHAR(SYSDATE,'DD') DD,TO_CHAR(SYSDATE,'MM') MM FROM DUAL轉成SQLSERVER
在Oracle数据库中,`SYSDATE` 是用来获取当前系统日期和时间的一个函数。`TRUNC(SYSDATE)` 是用来获取当前系统日期(不包含时间部分)。计算 `(SYSDATE-TRUNC(SYSDATE))*24` 的结果是获取当前系统时间的小时数。`TO_CHAR(SYSDATE,'DD')` 和 `TO_CHAR(SYSDATE,'MM')` 分别是将当前日期格式化为日和月的字符串。
在SQL Server中,等效的操作可以通过 `GETDATE()` 函数来实现,该函数返回当前的日期和时间。使用 `CONVERT` 函数或者 `FORMAT` 函数(在SQL Server 2012及以上版本可用)可以将日期时间格式化为特定的字符串格式。
将上述Oracle SQL语句转换为SQL Server的等效语句如下:
```sql
SELECT
DATEDIFF(HOUR, 0, GETDATE()) AS NOWDATE,
RIGHT('0' + CONVERT(VARCHAR, DAY(GETDATE())), 2) AS DD,
RIGHT('0' + CONVERT(VARCHAR, MONTH(GETDATE())), 2) AS MM
FROM
sys.dual
```
这里使用 `DATEDIFF` 函数来计算当前时间与当天0点之间的小时数。`CONVERT` 函数将日期部分转换为字符串,`RIGHT` 函数确保日和月始终是两位数字的字符串(如果不足两位,前面补0)。
TRUNC( ( to_char( SYSDATE, 'yyyyMMdd' ) - to_char( BIRTH_DATE, 'yyyyMMdd' ) ) / 10000 ) AS age
The above SQL code calculates the age of a person based on their birth date and the current date.
Explanation of the code:
- SYSDATE is a built-in function in Oracle that returns the current system date and time.
- to_char() is a function that converts a date or timestamp value to a character string in a specified format.
- 'yyyyMMdd' is the date format used in this code, where 'yyyy' represents the year with four digits, 'MM' represents the month with two digits, and 'dd' represents the day with two digits.
- BIRTH_DATE is a column name in a table that stores the birth date of a person.
- The subtraction of the birth date from the current date yields the number of days between the two dates. This value is divided by 10000 to convert the number of days to years.
- TRUNC() is a function that truncates a number to a specified number of decimal places. In this code, it is used to remove any fractional part from the age value.
Overall, the code calculates the age of a person by subtracting their birth date from the current date, converting the result from days to years, and truncating any fractional part.
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