Oracle changes session Date Format

Description of Oracle session date format change: the conversion time in the stored procedure should be output in 'yyyy-mm-dd' format, but the output result is not in this format, for example, after '2017-12-31 ', the output is '31-March 12-12'. Solution: If you have checked the information for half a day, you will not be able to say that you have not found the correct keyword, the middle is not easy to find a post with the same problem, there is a layer of the main just said the sentence directly set alter session set NLS_DATE_FORMAT = '| ''' YYYY-MM-DD ''tried, no effect. I set it directly in PL/SQL. Then the running of the stored procedure was ineffective. After a long time, it was not solved. When I was about to give up, I suddenly got inspired to add this sentence to the stored procedure, O. It may be because I am stupid and cannot understand what the previous layer master said. There is a problem. There are two vertical lines in the format. I don't know what the function is, and I didn't try it. Execute immediate 'alter session set NLS_DATE_FORMAT = '| '''dd-MON-RRRR '''; execute immediate 'alter session set NLS_DATE_LANGUAGE =' | '''american '''; (3) in linux: oracle user editing. add the following content under bash_profile: export NLS_DATE_FORMAT = 'yyyy-MM-DD HH24: MI: ss' log on again to take effect (4) log On With sysdba and then update the props $ field in the table to update props $ set value = 'yyyy-MM-DD HH24: MI: s' where parameter = 'nls _ DATE_FORMAT ';