ISJSON()

ISJSON tests whether a string contains valid JSON.

Signature

ISJSON ( expression [, json_type_constraint] )

Parameters

  • expression — The string to test.
  • json_type_constraint — Specifies the JSON type to check in the input. Valid values are `VALUE`, `ARRAY`, `OBJECT`, or `SCALAR`. Introduced in SQL Server 2022.

Examples

SELECT ISJSON('true', VALUE);
1

Run against SQL Server 16.0.4265.3 on 2026-09-13. This is the output we got, not the documentation’s.

Available on

  • SQL Server 2017 and later
  • Azure SQL Database
  • Azure SQL Managed Instance
  • Azure Synapse Analytics
  • Microsoft Fabric warehouse
  • Fabric SQL database

Signature and description adapted from the Microsoft SQL documentation, used under the CC BY 4.0. SQL Server and Azure are trademarks of the Microsoft group of companies. This page is not affiliated with Microsoft.