SQL Server Error Troubleshooting

Capture the complete SQL Server error number, message, and server version before changing a query or schema. These guides explain common message numbers and show how to diagnose the underlying cause:

Conversion and numeric errors

• Error 245: Conversion failed from varchar to int — identify invalid text or implicit type conversions.
• Error 8115: Arithmetic overflow — check integer expressions, aggregates, and numeric ranges.

Grouping errors

• Error 8120: Column is not in GROUP BY — decide which values define the grouping level or use a window aggregate to retain detail rows.

Required-column errors

• Error 515: Cannot insert NULL into a NOT NULL column — distinguish explicit NULL from omitted columns and defaults.