How to fix Error 498 on Windows Server 2025 / Windows 11

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Troubleshooting Guide: SQL Server Error 498 – Invalid TABLESAMPLE or REPEATABLE Clause Value

Why This Error Happens

Error 498 occurs when the numeric argument passed to the TABLESAMPLE clause (such as a percentage or row count) or the seed value in the REPEATABLE clause falls outside the valid acceptable range or data type boundaries. This is typically caused by a query passing a negative number, a non-integer value where an integer is expected, or a seed value that exceeds the bigint limit. It can also occur when the value is derived from a variable or expression that evaluates to NULL or an unsupported data type at runtime.

Step-by-Step Resolution Guide

Step 1: Review the TABLESAMPLE Syntax in the Query

  • Check that the sampling method is correctly specified as either TABLESAMPLE SYSTEM (n PERCENT) or TABLESAMPLE SYSTEM (n ROWS).
  • Ensure n is a positive numeric literal or an expression that resolves to a valid non-negative value (percentages must be between 0 and 100).
  • Example of a corrected query:
  SELECT * FROM Sales.Orders
  TABLESAMPLE SYSTEM (10 PERCENT)
  REPEATABLE (100);

Step 2: Validate the REPEATABLE Seed Value

  • Confirm the seed value used in REPEATABLE (seed) is a valid integer within the bigint range (-9223372036854775808 to 9223372036854775807).
  • If the seed is being passed as a variable, verify its declared data type matches an integer type and is not NULL.
  • Example check in T-SQL:
  DECLARE @Seed INT = 100;
  SELECT * FROM Sales.Orders
  TABLESAMPLE SYSTEM (10 PERCENT)
  REPEATABLE (@Seed);

Step 3: Inspect Dynamic SQL or ORM-Generated Queries

  • If the query is generated dynamically (via application code, Entity Framework, or a stored procedure), log the final generated SQL string before execution.
  • Look for string concatenation errors that might insert malformed or empty values into the TABLESAMPLE or REPEATABLE clauses.
  • Use SQL Server Profiler or Extended Events (sqlserver.sql_statement_starting) to capture the exact query text causing the error.

Step 4: Update Statistics and Check Table Compatibility

  • Ensure the target table is not a view, as TABLESAMPLE only works on physical tables.
  • Run sp_helpindex or check sys.tables to confirm the object type.
  • Update statistics using:
  UPDATE STATISTICS Sales.Orders;
  • Retry the query after confirming statistics are current, as outdated metadata can sometimes cause unexpected evaluation errors in sampling operations.

Alternative or Verification Steps

  • Run the corrected query in SQL Server Management Studio (SSMS) or Azure Data Studio and confirm it executes without Error 498, returning a sampled subset of rows.
  • As an alternative, replace TABLESAMPLE with a manual sampling approach using ORDER BY NEWID() combined with TOP (n) if the sampling clause continues to cause issues in automated scripts or ORM-generated queries.