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Description

This error indicates that a SQL query references a window name within an `OVER` clause or a `WINDOW` clause that MySQL cannot find. It typically occurs when the specified window name has not been properly defined or is misspelled, preventing the database from executing the window function.

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Error Message

Window name '%s' is not defined.

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Known Causes

3 known causes

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Typo in Window Name

The window name referenced in the `OVER` clause does not exactly match the name defined in the `WINDOW` clause due to a spelling error or incorrect casing.

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Missing Window Definition

The SQL query attempts to use a window name that has not been declared at all within a `WINDOW` clause or directly in the `OVER` clause.

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Incorrect Scope or Placement

The window definition exists but is not accessible in the current query block or scope where it is being referenced, for example, defined in a subquery but used in the outer query.

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Solutions

4 solutions available

1. Verify Window Function Name Spelling easy

Ensure the window function name in your query exactly matches its definition.

1

Carefully review your SQL query where you are using a window function.

2

Locate the `OVER (...)` clause. Inside the parentheses, you should see a window name (e.g., `OVER my_window`).

SELECT column1, SUM(column2) OVER my_window FROM my_table;

3

Find where `my_window` is defined, typically using the `WINDOW` clause.

WINDOW my_window AS (PARTITION BY column3 ORDER BY column4);

4

Compare the window name used in the `OVER` clause with the name defined in the `WINDOW` clause. Ensure there are no typos, case mismatches, or extra/missing characters.

2. Define the Window Before Usage easy

Make sure the window function is explicitly defined using the `WINDOW` clause before it is referenced.

1

Confirm that your query structure includes the `WINDOW` clause.

2

The `WINDOW` clause should appear after `WHERE`, `GROUP BY`, and `HAVING` clauses, but before `ORDER BY` and `LIMIT`.

SELECT 
    column1, 
    SUM(column2) OVER my_window AS window_sum
FROM 
    my_table
WHERE 
    ...
GROUP BY 
    ...
HAVING 
    ...
WINDOW 
    my_window AS (PARTITION BY column3 ORDER BY column4) 
ORDER BY 
    column1;

3

If you are defining multiple windows, ensure each is correctly named and defined within the `WINDOW` clause, separated by commas.

WINDOW window1 AS (...), window2 AS (...);

3. Check MySQL Version Compatibility medium

Window functions are available from MySQL 8.0 onwards. Ensure your version supports them.

1

Connect to your MySQL server using a client.

2

Execute the following command to check your MySQL version.

SELECT VERSION();

3

If your MySQL version is older than 8.0, window functions are not supported. You will need to upgrade your MySQL server to a compatible version to use them.

4

Alternatively, if upgrading is not an option, you will need to rewrite your query to achieve the desired result using subqueries or other methods that do not rely on window functions.

4. Use Inline Window Definitions for Simplicity easy

For simpler cases, define the window directly within the `OVER` clause instead of using a separate `WINDOW` clause.

1

If you are only using one or two window definitions and they are not overly complex, consider defining them inline.

2

Replace the `WINDOW` clause with the window definition directly inside the `OVER` clause.

SELECT 
    column1, 
    SUM(column2) OVER (PARTITION BY column3 ORDER BY column4) AS window_sum
FROM 
    my_table;

3

This approach avoids the need for naming the window explicitly, thus preventing the 'Undefined Window Function Name' error if the name was misspelled or not properly defined.

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Related Errors

5 related errors

MySQL Error 3579: Undefined Window Function Name