What are the reasons for the oracle error ORA-01830?

ORA-01830 is an error code in Oracle database, indicating an invalid date format. There are several possible reasons for this error to occur.

1. Incorrect date format: There is no matching between the date string and the date format. For example, using the wrong date format or a date string that does not match the format.

2. Incorrect time zone setting: The database’s time zone setting does not match the date format being used. This could be due to an incorrect time zone setting in the database or using mismatched date formats and strings under different time zone settings.

3. Type mismatch: trying to convert a string that does not match the date format into a date type. For example, when converting a string to a date type, the format of the string does not match the format of the date type.

4. Incomplete or missing data: The necessary date parts, such as year, month, day, are missing from the date string.

Implicit conversion error: There may be implicit conversion errors in database queries, leading to mismatched date formats.

Setting the NLS_DATE_FORMAT parameter incorrectly can result in date format mismatch errors.

7. Other reasons: There may be other factors that result in the ORA-01830 error, such as incompatible database versions or incorrect database configurations.

It is necessary to analyze and resolve the error based on the specific situation. The error can be identified by checking the date format, strings, time zone settings, data types, and the NLS_DATE_FORMAT parameter, and making the necessary adjustments and fixes.