What Is a JSON Property Indexes with Computed Columns in Microsoft SQL Server?
A computed column extracts and types a stable JSON path, then a normal index accelerates filters on that property.
How the JSON Property Indexes with Computed Columns Algorithm Works
A computed column extracts and types a stable JSON path, then a normal index accelerates filters on that property.
When to Use JSON Property Indexes with Computed Columns
Frequently filtered or joined JSON fields whose path and type are stable.
How to Create a Microsoft SQL Server JSON Property Indexes with Computed Columns
Review data quality, existing structures, feature support, build time, and deployment requirements before creating an index on a production table.
ALTER TABLE dbo.Events ADD EventType AS CONVERT(nvarchar(40), JSON_VALUE(Payload, '$.type'));
CREATE INDEX IX_Events_EventType ON dbo.Events (EventType);JSON Property Indexes with Computed Columns Query Example
This example demonstrates the matching query shape. Check the execution plan to confirm that the engine can use the index.
SELECT EventId FROM dbo.Events WHERE EventType = N'purchase';Queries Supported by JSON Property Indexes with Computed Columns
Frequently filtered or joined JSON fields whose path and type are stable. A similar-looking predicate may not use the same access path; operators, expressions, key order, and data type all matter.
Read Performance, Storage, and Write Costs
Expression and index maintenance add write costs; JSON parsing/conversion and collation matter. Indexes reduce some search work but require storage and add maintenance to writes.
JSON Property Indexes with Computed Columns Limitations and Common Mistakes
Native JSON index features are version-specific; computed-column indexing is established but expression compatibility matters.
Do not assume that an index being present means the optimizer chose it or that the query became selective.
How to Measure and Tune JSON Property Indexes with Computed Columns
Use EXPLAIN/actual plan to confirm use; keep path and conversion deterministic and query consistently.
Compare representative plans and timings before and after, including concurrent writes and realistic data volumes.
JSON Property Indexes with Computed Columns Questions
Will the database always use this index?
No. The optimizer weighs selectivity, estimated costs, statistics, cache state, and the amount of data returned.
What should I verify before production?
Confirm version support, query compatibility, write overhead, build/rollback procedures, and index behavior during backup and recovery.
Official Microsoft SQL Server Index Documentation
Check Microsoft Learn: SQL Server Indexes for release-specific requirements and supported operators.