Oracle Date conversion ORA-01810: Format code appears two times 01810. 00000-"Format code appears twice"

Describe

Execute the following SQL

selectTO_DATE(‘2018-1-9 12:41:00‘,‘yyyy-MM-dd hh24:mm:ss‘from dual;

And then I reported the following error.

ORA-01810: Format code appears two times

1. 00000-"Format code appears twice"
   Cause:
   Action:
   Select Receivedate,receivetime,to_date (concat (Receivedate,concat ('), receivetime), ' Yyyy-mm-dd hh24:mm:ss ') from Workflow_currentoperator where RequestID = Nodeid = 162;

Causes and Solutions

The syntax for the TO_DATE function is as follows:

TO_DATE(char,fmt);

Where Char is a string, and FMT is a date format, such as yyyy-mm-dd hh24:mi:ss .

For SQL syntax is case-insensitive, so the date format of mm and MM is the same, in Oracle's date conversion for the month should be used MM , for minutes should be used MI . SQL should be modified to read as follows:

selectTO_DATE(‘2018-1-9 12:41:00‘,‘yyyy-MM-dd hh24:mi:ss‘from dual;

The time-date format for Oracle is the following table:

Elements	Description
Dd	Days of the Month (1-31).
YYYY	Year
Mm	Month (01-12; January = 01).
HH	Time (12-hour system)
HH12	Time (12-hour system)
HH24	Time (24-hour system)
MI	Minutes
Ss	Seconds

This is not the same as the Java time-date format, and the Java time-date format is the following table:

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");sdf.format(date);

Letter

	Date or Time Component	Presentation	Examples
G	Era designator	Text	AD
y	Year	Year	1996; 96
Y	Week year	Year	2009; 09
M	Month in year (context sensitive)	Month	July; Jul; 07
L	Month in year (standalone form)	Month	July; Jul; 07
w	Week in year	Number	27
W	Week in month	Number	2
D	Day in year	Number	189
d	Day in month	Number	10
F	Day's week in month	Number	2
E	Day name in week	Text	Tuesday; Tue
u	Day number of week (1 = Monday, ..., 7 = Sunday)	Number	1
a	AM/PM Marker	Text	PM
H	Hour in Day (0-23)	Number	0
k	Hour in Day (1-24)	Number	24
K	Hour in AM/PM (0-11)	Number	0
h	Hour in AM/PM (1-12)	Number	12
m	Minute in Hour	Number	30
s	Second in minute	Number	55
S	Millisecond	Number	978
z	Time zone	General Time Zone	Pacific Standard Time; PST; GMT-08:00
Z	Time zone	RFC 822 Time Zone	-0800
X	Time zone	ISO 8601 time Zone	-08; -0800;-08:00

Reference

1.https://docs.oracle.com/cd/e11882_01/server.112/e41084/functions203.htm#sqlrf06132
2.https://docs.oracle.com/cd/e11882_01/server.112/e41084/sql_elements004.htm#sqlrf00212
3.java.text.simpledateformat

Oracle Date conversion ORA-01810: Format code appears two times 01810. 00000-"Format code appears twice"