S:select getdate() value O:select sysdate value from dual 36.前后几日 直接与整数相加减 37.求日期 S:select convert(char(10),getdate(),20) value O:select trunc(sysdate) value from dual select to_char(sysdate, ‘yyyy-mm-dd ‘) value from dual 38.求时间 S:select convert(char(8),get...
日期时间型:DATE, DATETIME, DATETIME2, TIME 浮点型:FLOAT, REAL, DECIMAL 每种数据类型都有其特定的用途,开发者需要根据业务需求选用合适的数据类型。 4. 过滤和排序数据 使用WHERE子句可以对查询结果进行过滤,使用ORDER BY子句可以对结果进行排序。 sql SELECT * FROM table_name WHERE condition ORDER BY column...
This function collapses a date/time to a fixed interval, eliminating the need to round datetime values, extract date parts, perform wild conversions to and from other types like float, or make elaborate and unintuitive dateadd/datediff calculations (sometimes using magic dates from the past). The...
However, GETDATE will return the current datetime value, which will change even if nothing in your database has changed. T-SQL Functions Types of T-SQL functions include: Aggregate Functions Aggregate functions can perform a calculation on a set of values but will return one value. These ...
CURTIME():This is also the date format function that can give back the current time. EXTRACT():This function can give back a single part or time. DATE_SUB():This function can subtract a particular time interval from a date. DATE_FORMAT():It can present the date or time in various for...
Data Types and Operators:SQL supports a wide range of standard data types, such as integers, strings, and dates. T-SQL, however, extends these data types to include proprietary types likeunique identifier(for GUIDs) anddatetime2(for more precise date/time values). Additionally, T-SQL includes...
s:可以直接转或者selectcast('2004-09-08'asdatetime) value o:selectto_date('2004-01-05 22:09:38','yyyy-mm-dd hh24-mi-ss') vaulefromdual;43.求两日期某一部分的差(比如秒) s:selectdatediff(ss,getdate(),getdate()+12.3) value
extract date from text string - Transact-SQL Extract directory path from the file path with file name Extract Image data (storing xml file) from sql server table, shred xml file and load to table Extract integer portion? Extract multiple strings between multiple characters in SQ...
UNIX_TIMESTAMP(date) 示例: 假设有一个名为 orders 的表,其中包含一个名为 order_date 的列,该列的数据类型为 DATETIME。 SELECT UNIX_TIMESTAMP(order_date) AS timestamp FROM orders; 这将返回每个订单日期的时间戳。 2. PostgreSQL 在PostgreSQL中,可以使用 EXTRACT(EPOCH FROM ...) 将日期或时间转换...
bool('') == False bool(0) == False 所有变量的位操作都是通过强制转换成bool实现的，并且表达式...