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Description

This error indicates that a `SELECT` statement's `OFFSET` clause was provided with a negative or otherwise invalid row count. The `OFFSET` clause determines how many rows to skip before fetching results, and this value must be zero or a positive integer. It typically arises from incorrect application logic or dynamic SQL generation.

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Error Message

invalid row count in result offset clause

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Known Causes

4 known causes

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Incorrect Application Logic

The application code calculating the `OFFSET` value for a query produced a negative number due to a bug, miscalculation, or unexpected input data.

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Flawed Dynamic SQL Generation

When constructing SQL queries dynamically, a negative value was inadvertently inserted into the `OFFSET` clause due to string concatenation errors or unvalidated variables.

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Explicit Negative Offset

The SQL query explicitly specified a negative integer literal directly within the `OFFSET` clause, which PostgreSQL interprets as an invalid row count.

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Data Conversion Problems

An implicit or explicit data type conversion of a variable intended for the `OFFSET` clause resulted in an unexpected negative numerical value.

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Solutions

3 solutions available

1. Correct Negative Offset Value easy

Ensure the OFFSET value in your SQL query is non-negative.

1

Locate the SQL query that is producing the error. This error typically occurs when using the `OFFSET` clause in your `SELECT` statement.

2

Examine the `OFFSET` clause. The value provided to `OFFSET` must be zero or a positive integer.

SELECT column1, column2 FROM your_table ORDER BY column1 OFFSET -10;

3

Modify the query to use a valid non-negative offset. If you intended to skip a certain number of rows, use a positive integer. If no rows should be skipped, use `OFFSET 0` or omit the `OFFSET` clause entirely.

SELECT column1, column2 FROM your_table ORDER BY column1 OFFSET 10; -- Corrected to a positive offset
-- OR
SELECT column1, column2 FROM your_table ORDER BY column1 OFFSET 0; -- No rows skipped

2. Validate Dynamic Offset Generation medium

If the OFFSET value is generated dynamically, ensure the logic prevents negative numbers.

1

Identify where the `OFFSET` value is being determined. This might be in application code (e.g., Python, Java, Node.js) or within a stored procedure/function.

2

Review the code responsible for calculating the offset. Look for any operations or conditions that could result in a negative number being assigned to the offset variable.

// Example in JavaScript
let pageNumber = req.query.page;
let pageSize = 10;
let offset = (pageNumber - 1) * pageSize;
// If pageNumber is 0 or negative, offset could become negative.

3

Implement checks to ensure the offset is always non-negative. A common approach is to use `Math.max(0, calculated_offset)` or similar logic in your programming language.

// Example in JavaScript
let pageNumber = parseInt(req.query.page) || 1;
let pageSize = 10;
let offset = Math.max(0, (pageNumber - 1) * pageSize);

// Example in Python
page_number = int(request.args.get('page', 1))
page_size = 10
offset = max(0, (page_number - 1) * page_size)

4

If using PostgreSQL functions or procedures, ensure any variables used for OFFSET are initialized to 0 or checked for negativity before being used in the query.

CREATE OR REPLACE FUNCTION get_paginated_data(offset_val INT) RETURNS SETOF your_table AS $$
BEGIN
  IF offset_val < 0 THEN
    offset_val := 0;
  END IF;
  RETURN QUERY EXECUTE 'SELECT * FROM your_table OFFSET ' || offset_val;
END;
$$ LANGUAGE plpgsql;

3. Review Query Generation Logic in ORMs/Libraries medium

Ensure your Object-Relational Mapper (ORM) or database access library is generating valid SQL.

1

If you are using an ORM (e.g., SQLAlchemy, Hibernate, TypeORM, Sequelize) or a database access library, examine how it handles pagination parameters.

2

Consult the documentation for your specific ORM/library regarding its pagination features. Understand how it translates page numbers and limits into `OFFSET` and `LIMIT` clauses.

3

Check the values passed to the ORM's pagination methods. Ensure that page numbers are handled correctly, especially for the first page (which should typically result in an `OFFSET` of 0).

// Example with Sequelize (Node.js)
YourModel.findAll({
  offset: (page - 1) * limit,
  limit: limit
});
// Ensure 'page' is handled to avoid (1-1)*limit becoming negative if page is 0 or invalid.

4

If possible, inspect the generated SQL query from your ORM to confirm that the `OFFSET` clause is always a non-negative integer.

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Related Errors

5 related errors

PostgreSQL Error 2201X: Negative Offset Row Count