Oracle system functions, user-defined functions, and keywords

Oracle system functions, user-defined functions, and keywords are used to collect Oracle knowledge points that are commonly used at work, constantly updated and accumulated. Just use it as your own notebook.

Oracle system functions, user-defined functions, and keywords are used to collect Oracle knowledge points that are commonly used at work, constantly updated and accumulated. Just use it as your own notebook.

Oracle system functions, user-defined functions, and keywords

[Date: 2012-06-16] Source: Linux Author: baolong47 [Font:]

Question: Collect Oracle knowledge points that are commonly used at work, constantly update and accumulate, and use them as your own notebook.

Some keywords

1Is not null, to judge whether the field IS NULL

2 case when... THEN... ELSE... END, Condition Statement

3 EXITS, not exits, to determine whether it exists, usually placed behind the WHERE

Some system functions

1. TO_CHAR ()

Display: 10:11:45

2. Convert TO_DATE () to a certain format of time

The time parameter can be:

Some customFunction

1. Write the CHECK_DEMAND_IS_NOTICE function used by a job. The function needs to input data of the NUMBER type, and a data of the VARCHAR2 type is returned.