oracle julian date conversion

Detailed Connection: http://blog.163.com/lsj_start/blog/static/17826443920111112103716524/http://blog.itpub.net/29324876/viewspace-1096741/(view implicit conversion with explain)Oracle has three of the most basic data types, namely, character, numeric, and date. also provides a type conversion function1)To_char Numeri

Processing date in Oracle To_date formatDay:Dd number 12Dy abbreviated FriDay spelled out FridayDdspth spelled out, ordinal twelfthMonth:MM number 03Mon abbreviated MARMonth spelled out MarchYear:YY two digits 98Yyyy four digits 1998 The time range in the 24-hour format is: 0:00:00-23:59:59 ....The time range in the 12-hour format is: 1:00:00-12:59:59 ....1.Date

Processing date in Oracle To_date formatDay:Dd number 12Dy abbreviated FriDay spelled out FridayDdspth spelled out, ordinal twelfthMonth:MM number 03Mon abbreviated MARMonth spelled out MarchYear:YY two digits 98Yyyy four digits 1998 The time range in the 24-hour format is: 0:00:00-23:59:59 ....The time range in the 12-hour format is: 1:00:00-12:59:59 ....1.Date

, select 1 | '2' from dual;-> select to_char (1) | '2' from dual; 8) During arithmetic operations on and comparisons between characterand noncharacter datatypes, oracle converts from any character datatype to anumber, date, or Rowid, as appropriate. in arithmetic operations betweenCHAR/VARCHAR2 and NCHAR/NVARCHAR2, Oracle converts to a number. if data of the char

To_timestamp (' 2012-7-28 03:12:00 ', ' yyyy-mm-dd hh24:mi:ss ')-systimestamp from dualThe result: +000000092 05:51:24.032000000, a little intercept, you can get 92 days 5 hours, 51 minutes, 24 seconds, so users look more intuitive! But this number is not very intuitive for programmers, if you want a specific length of time, and the accuracy is not required to milliseconds, you can convert the timestamp type to date type, and then directly subtract.T

through index range scan. However, by default, oracle CBO does not select the index location. For example, oracle uses table full scan. Why? This type of problem occurs only when TIMESTAMP is introduced after oracle version 9.2. Before 9.2, Oracle only had DATE, but not TIM

In the development of Oracle databases, it is often a matter of time, so the date function of Oracle data is collected specifically. is for future investigation. Add_months (d,n) Date d plus n months Last_day (d) The date of the last day of the month that contains D New_time

There are many date functions in oracle, such: 1,Add_months ()Used to increase or decrease the number of months from a date value. Date_value: = add_months (date_value, number_of_months) Example: SQL> select add_months (sysdate, 12) "Next Year" from dual; Next Year ---------- April 11-04 SQL> select add_months (sysdate, 112) "Last Year" from dual; Last Year ----

, you are looking for every Friday date in the first three months of the current month.9.oracle Medium Time operationThe contents are as follows:1, Oracle supports the operation of the date2, the date is calculated in days as a unit3, when it is necessary to calculate the value of smaller units, such as seconds, time-b

monthSelect To_char (T.D, ' Yy-mm-dd ') from (Select Trunc (sysdate, ' MM ') +rownum-1 as DFrom Dba_objectswhere RowNum where To_char (T.D, ' mm ') = To_char (sysdate, ' mm ')--Find the Friday date of the current monthand Trim (To_char (T.D, ' Day ')) = ' Friday '--------11-05-0211-05-0911-05-1611-05-2311-05-30If you change where To_char (T.D, ' mm ') = To_char (sysdate, ' mm ') to sysdate-90, you are looking for every Friday