FEATURE: SQL 2025 Native JSON Support

.github/workflows/pr-validation.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       matrix:
         go: ['1.24']
-        sqlImage: ['2019-latest','2022-latest']
+        sqlImage: ['2017-latest','2019-latest','2022-latest','2025-latest']
     steps:
     - uses: actions/checkout@v2
     - name: Setup go
@@ -26,7 +26,15 @@ jobs:
         export SQLUSER=sa
         export SQLPASSWORD=$SQLCMDPASSWORD
         export DATABASE=master
-        export HOST=.
+        export HOST=localhost
+        # Build connection string - SQL 2017 requires trusting its self-signed certificate
+        if [ "${{ matrix.sqlImage }}" = "2017-latest" ]; then
+          export SQLSERVER_DSN="sqlserver://${SQLUSER}:${SQLPASSWORD}@localhost:1433?database=${DATABASE}&trustServerCertificate=true"
+          # SQL 2017's certificate has a negative serial number which Go 1.23+ rejects by default
+          export GODEBUG=x509negativeserial=1
+        else
+          export SQLSERVER_DSN="sqlserver://${SQLUSER}:${SQLPASSWORD}@localhost:1433?database=${DATABASE}"
+        fi
         docker run -m 2GB -e ACCEPT_EULA=1 -d --name sqlserver -p:1433:1433 -e SA_PASSWORD=$SQLCMDPASSWORD mcr.microsoft.com/mssql/server:${{ matrix.sqlImage }}
         sleep 10
         go test -v ./...

CHANGELOG.md

@@ -1,4 +1,14 @@
 # Changelog
+
+## Unreleased
+
+### Features
+
+* Add `mssql.JSON` and `mssql.NullJSON` types for working with JSON data
+  - Uses native JSON type (0xF4) on SQL Server 2025+ and Azure SQL Database
+  - Automatically falls back to `nvarchar(max)` on SQL Server 2016-2022 for seamless compatibility
+  - Works with SQL Server's built-in JSON functions (JSON_VALUE, JSON_QUERY, ISJSON, etc.) on all supported SQL Server versions (2016+)
+
 ## 1.9.3
 
 ### Bug fixes

README.md

@@ -431,6 +431,8 @@ are supported:
 
 * string -> nvarchar
 * mssql.VarChar -> varchar
+* mssql.JSON -> json (SQL Server 2025+) or nvarchar(max) (older versions)
+* mssql.NullJSON -> json (nullable, SQL Server 2025+) or nvarchar(max) (older versions)
 * time.Time -> datetimeoffset or datetime (TDS version dependent)
 * mssql.DateTime1 -> datetime
 * mssql.DateTimeOffset -> datetimeoffset
@@ -454,6 +456,41 @@ db.QueryContext(ctx, `select * from t2 where user_name = @p1;`, mssql.VarChar(na
 // Note: Mismatched data types on table and parameter may cause long running queries
 ```
 
+### JSON Type
+
+The driver provides `mssql.JSON` and `mssql.NullJSON` types for working with JSON data. These types work seamlessly across all supported SQL Server versions with automatic fallback behavior.
+
+**Server Compatibility:**
+- **SQL Server 2025+ / Azure SQL Database**: Uses the native JSON data type (type ID 0xF4) for optimal performance and type safety
+- **SQL Server 2016-2022**: Automatically falls back to `nvarchar(max)` parameter declaration, allowing JSON data to work with the built-in JSON functions (JSON_VALUE, JSON_QUERY, ISJSON, etc.)
+
+The driver automatically detects server capabilities during connection and chooses the appropriate behavior. You can use the same `mssql.JSON` and `mssql.NullJSON` types regardless of the SQL Server version - no code changes required.
+
+**Note:** Native JSON *columns* (using the JSON data type in CREATE TABLE) require SQL Server 2025+ or Azure SQL Database. On older versions, store JSON in `nvarchar(max)` columns.
+
+```go
+// Insert JSON data
+jsonData := json.RawMessage(`{"name":"John","age":30,"active":true}`)
+_, err := db.ExecContext(ctx, "INSERT INTO users (profile) VALUES (@p1)", mssql.JSON(jsonData))
+
+// Insert nullable JSON
+nullableJSON := mssql.NullJSON{JSON: json.RawMessage(`{"key":"value"}`), Valid: true}
+_, err = db.ExecContext(ctx, "INSERT INTO users (metadata) VALUES (@p1)", nullableJSON)
+
+// Insert NULL JSON value
+nullJSON := mssql.NullJSON{Valid: false}
+_, err = db.ExecContext(ctx, "INSERT INTO users (metadata) VALUES (@p1)", nullJSON)
+
+// Read JSON data
+var result mssql.NullJSON
+err = db.QueryRowContext(ctx, "SELECT metadata FROM users WHERE id = @p1", 1).Scan(&result)
+if result.Valid {
+    fmt.Println("JSON data:", result.JSON)
+} else {
+    fmt.Println("JSON is NULL")
+}
+```
+
 ## Using Always Encrypted
 
 The protocol and cryptography details for AE are [detailed elsewhere](https://learn.microsoft.com/sql/relational-databases/security/encryption/always-encrypted-database-engine?view=sql-server-ver16).
@@ -529,6 +566,7 @@ Constrain the provider to an allowed list of key vaults by appending vault host
 * Can be used with Microsoft Azure SQL Database
 * Can be used on all go supported platforms (e.g. Linux, Mac OS X and Windows)
 * Supports new date/time types: date, time, datetime2, datetimeoffset
+* Supports JSON data with automatic fallback (SQL Server 2016+, native JSON type in 2025+)
 * Supports string parameters longer than 8000 characters
 * Supports encryption using SSL/TLS
 * Supports SQL Server and Windows Authentication
@@ -586,6 +624,8 @@ More information: <http://support.microsoft.com/kb/2653857>
 
 * Bulk copy does not yet support encrypting column values using Always Encrypted. Tracked in [#127](https://github.com/microsoft/go-mssqldb/issues/127)
 
+* The JSON data type is not supported with Always Encrypted. This is a SQL Server limitation - the JSON type is not included in the list of [supported data types for Always Encrypted](https://learn.microsoft.com/en-us/sql/relational-databases/security/encryption/always-encrypted-cryptography).
+
 # Contributing
 This project is a fork of [https://github.com/denisenkom/go-mssqldb](https://github.com/denisenkom/go-mssqldb) and welcomes new and previous contributors. For more informaton on contributing to this project, please see [Contributing](./CONTRIBUTING.md).
 

integratedauth/winsspi/provider.go

@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 package winsspi
@@ -12,4 +13,4 @@ func init() {
 	if err != nil {
 		panic(err)
 	}
-}
+}

integratedauth/winsspi/winsspi.go

@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 package winsspi