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Description

This error indicates that a `CASE` statement in a stored procedure or function could not find a matching `WHEN` condition and also lacked an `ELSE` clause. It signifies an unhandled logical path within the `CASE` construct, preventing the statement from completing successfully.

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Error Message

Case not found for CASE statement

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Known Causes

3 known causes

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Missing ELSE Clause

A `CASE` statement executed without any `WHEN` condition matching and no `ELSE` clause present to handle default scenarios.

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Incomplete WHEN Conditions

The `WHEN` conditions within the `CASE` statement do not cover all possible input values or logical paths, leaving some unhandled.

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Unexpected Data Values

The input data being evaluated by the `CASE` statement contains values not explicitly handled by any `WHEN` clause.

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Solutions

3 solutions available

1. Ensure All Paths in CASE Statement are Handled easy

Modify the CASE statement to include an ELSE clause to catch any unhandled conditions.

1

Review your SQL query that is generating the error. Identify the `CASE` statement causing the issue.

2

Add an `ELSE` clause to the `CASE` statement. This clause will provide a default value if none of the `WHEN` conditions are met. This is the most common and straightforward fix.

SELECT 
    column1,
    CASE 
        WHEN condition1 THEN 'value1'
        WHEN condition2 THEN 'value2'
        ELSE 'default_value' -- Add this ELSE clause
    END AS handled_case
FROM your_table;

3

Test your query again to confirm the error is resolved.

2. Exhaustively List All Possible WHEN Conditions medium

Completely enumerate all potential values or conditions that the CASE statement might encounter.

1

Analyze the data source for the column or expression being evaluated in the `CASE` statement. Understand all possible values it can take.

SELECT DISTINCT your_column FROM your_table;

2

For each distinct value or possible condition identified, add a corresponding `WHEN` clause to your `CASE` statement.

SELECT 
    column1,
    CASE 
        WHEN your_column = 'value_a' THEN 'result_a'
        WHEN your_column = 'value_b' THEN 'result_b'
        WHEN your_column = 'value_c' THEN 'result_c'
        -- ... add WHEN clauses for all possible values
    END AS exhaustive_case
FROM your_table;

3

If there are still potential unhandled values after exhaustive listing, consider adding an `ELSE` clause as a fallback, though this might indicate a data integrity issue.

SELECT 
    column1,
    CASE 
        WHEN your_column = 'value_a' THEN 'result_a'
        WHEN your_column = 'value_b' THEN 'result_b'
        ELSE 'unhandled_or_error' -- Fallback for any unexpected values
    END AS handled_case
FROM your_table;

4

Execute the query to ensure the error is resolved.

3. Use CASE Expression with a Column Name Directly easy

Simplify the CASE statement by evaluating a single column or expression directly instead of multiple complex conditions.

1

Identify the column or expression that is the primary subject of your `CASE` statement.

2

Rewrite the `CASE` statement to evaluate this column directly, using `WHEN value THEN result` syntax. This often makes it clearer what values are being handled.

SELECT 
    column1,
    CASE your_column_to_evaluate 
        WHEN 'specific_value_1' THEN 'result_for_1'
        WHEN 'specific_value_2' THEN 'result_for_2'
        ELSE 'default_result'
    END AS simplified_case
FROM your_table;

3

Ensure all expected values for `your_column_to_evaluate` are covered by `WHEN` clauses or handled by the `ELSE` clause.

4

Run the query to verify the error is gone.

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Related Errors

5 related errors

MySQL Error 1339: Unhandled CASE Condition