Date functionDate functions manipulate Date values (fields of date type), timestamp values (TIMESTAMP, TIMESTAMP with time ZONE, and TIMESTAMP with the fields of the local time ZONE type), and interval values (INTERVAL day to SECOND and INTERVAL
Visual existing electronic scale, using a serial port to communicate with the computer. Write VB program to access the serial port, to read the data displayed on the electronic scale. The electronic scale is BE01 type instrument, output is rs-232c
Internal storage format:
century, year, month, day, hour, minute, second
The default format is: DD-MON-RR.
Sysdate returns the current system time.
SELECT sysdate from DUAL;
The mathematical operation of a date
SELECT (sysdate-hire_date)/7 from
Sysdate[Function]: returns the current date. [Parameter]: No parameter, no brackets [Return]: Date [Example] select sysdate hz from dual; return:
Add_months (d1, n1)[Function]: return the new date after the date d1 plus the n1 month. [Parameter]: d1,
Numeric type functions:Absolute:ABS (x) "function" returns the absolute value of x "parameter" x, numeric Expression "return" number "example" Select ABS (+), ABS ( -100) from dual;--------------------------------------------------------------------
---------------------------------------------Date/Time function-------------------------------------------------1:sysdateThe current date used to get the systemSELECT sysdate from DUAL;--2:add_monthsAdd or subtract a monthSELECT To_char (add_months (
SysdateFeature: Returns the current date."Parameters": no arguments, no parentheses"Back": Date
2Add_months (D1,N1)"Function": Returns the new date after the date D1, plus N1 months."Parameters": D1, Date type, N1 digital type"Back": Date
Article Source: http://www.cnblogs.com/zfc2201/p/3284965.htmlDate formatting: Alter session set nls_date_format= ' Yyyy-mm-dd hh24:mi:ss dy 'Note: The HH24 format cannot be set to am pm on PM Indicatorsysdate"function": Returns the current date.
Sysdate [function]: returns the current date. [Parameter]: No parameter, no brackets [Return]: Date [Example] select sysdate hz from dual; return:
Last_day (d1) [function]: return the date of the last day of the month where the date d1 is located. [
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