Oracle Error ORA-01861: Literal Does Not Match Format String - Resolution Guide

The ORA-01861 error in Oracle databases signals a mismatch between the format of a date or timestamp literal and the format mask used in the conversion function (TO_DATE or TO_TIMESTAMP). This typically arises when attempting to convert a string value into a date or timestamp data type.

The error message indicates that the provided literal value doesn't adhere to the expected format string. This could stem from incorrect use of format elements, an incorrect sequence of elements within the format string, or improper element placement. For instance, if the format string anticipates a year in YYYY format but the literal value only has a year in YY format, the error will occur.

To rectify this error, meticulously examine the format string and the literal value employed in the conversion function. Ensure that the format string accurately reflects the format of the literal value. Verify that the elements within the format string are correctly sequenced and positioned. Additionally, confirm that any special characters or delimiters present in the format string are also included in the literal value.