Oracle Error PLS-00615: type mismatch found at ‘string’ between CASE operand and WHEN operands

Oracle Error Message

PLS-00615: type mismatch found at ‘string’ between CASE operand and WHEN operands

Reason for the Error

In a simple CASE statement or expression, the CASE operand and WHEN operands do not match in datatype, and it is unclear which implicit conversion is required to correct the mismatch.

Solution

Change the CASE operand and WHEN operands so that their datatypes match. Consider using datatype conversion functions in the CASE operand and/or WHEN operands.