How to diagnose and fix the 20000 case_not_found error code in Postgres.

by

The 20000 error code in PostgreSQL, labeled as case_not_found, is associated with a CASE statement in which none of the conditions are met and there is no ELSE branch to handle such a scenario. This is a class 20 error which indicates a Case Not Found for Case Statement situation.

To diagnose and fix this error, you should review your CASE statement to ensure that all possible conditions are accounted for. Here are some steps and examples to guide you:

  1. Diagnosis:
  • Look at the CASE statement that is causing the error.
  • Check if all possible values or conditions that can be encountered are covered by WHEN clauses.
  • Ensure that there is an ELSE clause to catch any cases that do not match the specified WHEN clauses.
  1. Fix:
  • Add an ELSE clause to handle any values that do not meet any of the WHEN conditions.
  • If the ELSE clause is not appropriate for your logic, make sure that your WHEN clauses cover all possible scenarios.
  1. Examples: Before fix (might cause 20000 error if my_column does not match any conditions):
   SELECT CASE my_column
     WHEN 'value1' THEN 'Result 1'
     WHEN 'value2' THEN 'Result 2'
   END
   FROM my_table;

After fix (with an ELSE clause to handle unexpected values):

   SELECT CASE my_column
     WHEN 'value1' THEN 'Result 1'
     WHEN 'value2' THEN 'Result 2'
     ELSE 'Default Result'
   END
   FROM my_table;

In the second example, if my_column does not match 'value1' or 'value2', the CASE statement will return 'Default Result', thus avoiding the 20000 error.

For more information on PostgreSQL error codes, you can refer to the official PostgreSQL Error Codes documentation.

Leave a Comment