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Description

This PostgreSQL error signifies that the `LIMIT` clause in your SQL query contains an invalid value for the number of rows to be returned. It typically occurs when the specified row count is not a positive integer or is otherwise syntactically incorrect, preventing the database from properly restricting the result set.

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Error Message

invalid row count in limit clause

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Known Causes

3 known causes

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Non-Positive or Zero Limit Value

Specifying a `LIMIT` value that is zero or a negative number will trigger this error, as the clause expects a positive integer to define the maximum number of rows.

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Non-Integer Value for Limit

Using a non-integer value, such as text, a decimal number, or any non-numeric type, within the `LIMIT` clause is invalid and will cause this data exception.

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Invalid Variable or Parameter Binding

If the `LIMIT` value is dynamically supplied by a variable or bound parameter, an incorrect data type or an invalid value in that variable can lead to this error.

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Solutions

3 solutions available

1. Correctly Format the LIMIT Clause easy

Ensure the LIMIT clause uses non-negative integer values.

1

Review your SQL query and locate the `LIMIT` clause. The `LIMIT` value must be a positive integer or zero. Negative values are not allowed.

SELECT * FROM your_table LIMIT 10;

2

If you are dynamically constructing the `LIMIT` value, ensure that the variable or expression evaluates to a non-negative integer before it's passed to the query. For example, if using a programming language, perform validation.

-- Example in Python (conceptual)
limit_value = -5 # This would cause the error
if limit_value < 0:
    limit_value = 0 # Or handle as an error
query = f"SELECT * FROM your_table LIMIT {limit_value};"

2. Handle Dynamic LIMIT Values Safely medium

Use parameterized queries or explicit casting to prevent invalid LIMIT values.

1

When passing `LIMIT` values from application code, always use parameterized queries to prevent SQL injection and ensure proper type handling. The database driver will typically handle type validation.

-- Example in Python with psycopg2
import psycopg2

conn = psycopg2.connect(database="your_db", user="your_user", password="your_password", host="your_host", port="your_port")
cur = conn.cursor()

limit_val = 10
cur.execute("SELECT * FROM your_table LIMIT %s;", (limit_val,))
results = cur.fetchall()

conn.close()

2

If you cannot use parameterized queries for some reason, explicitly cast the value to an integer and ensure it's non-negative before including it in the SQL string. This is less secure than parameterized queries.

SELECT * FROM your_table LIMIT CAST(COALESCE(your_limit_variable, 0) AS INTEGER) WHERE your_limit_variable >= 0;

3. Check for Invalid OFFSET Values easy

Ensure OFFSET clause values are also non-negative integers.

1

The `OFFSET` clause, often used in conjunction with `LIMIT` for pagination, also requires non-negative integer values. Review your query for any negative or invalid `OFFSET` values.

SELECT * FROM your_table LIMIT 10 OFFSET 5;

2

Similar to `LIMIT`, if `OFFSET` is dynamically generated, ensure it evaluates to a non-negative integer.

-- Example in PHP (conceptual)
$offset_value = -2; // This would cause an error
if ($offset_value < 0) {
    $offset_value = 0;
}
$query = "SELECT * FROM your_table LIMIT 10 OFFSET " . $offset_value;
// Execute query...

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Related Errors

5 related errors

PostgreSQL Error 2201W: Invalid LIMIT Clause Row Count