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Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
SQL database in Microsoft Fabric
Details
| Attribute | Value |
|---|---|
| Product Name | SQL Server |
| Event ID | 12301 |
| Event Source | MSSQLSERVER |
| Component | SQLEngine |
| Symbolic Name | HK_UNSUPPORTED_NULLABLE_COLUMNS |
| Message Text | Nullable columns in the index key are not supported with 'construct'. |
User Action
Do not use nullable columns in the index key.