Add overload that allows a custom parameter placeholder.

src/Marten/IAdvancedSql.cs

@@ -1,7 +1,9 @@
 #nullable enable
+using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
+using Marten.Internal.Sessions;
 
 namespace Marten;
 
@@ -20,6 +22,21 @@ public interface IAdvancedSql
     /// <returns></returns>
     Task<IReadOnlyList<T>> QueryAsync<T>(string sql, CancellationToken token, params object[] parameters);
 
+    /// <summary>
+    ///     Asynchronously queries the document storage with the supplied SQL.
+    ///     The type parameter can be a document class, a scalar or any JSON-serializable class.
+    ///     If the result is a document, the SQL must contain a select with the required fields in the correct order,
+    ///     depending on the session type and the metadata the document might use, at least id and data must be
+    ///     selected.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameters"></param>
+    /// <returns></returns>
+    Task<IReadOnlyList<T>> QueryAsync<T>(char placeholder, string sql, CancellationToken token, params object[] parameters);
+
     /// <summary>
     ///     Asynchronously queries the document storage with the supplied SQL.
     ///     The type parameters can be any document class, scalar or JSON-serializable class.
@@ -35,6 +52,23 @@ public interface IAdvancedSql
     /// <returns></returns>
     Task<IReadOnlyList<(T1, T2)>> QueryAsync<T1, T2>(string sql, CancellationToken token, params object[] parameters);
 
+    /// <summary>
+    ///     Asynchronously queries the document storage with the supplied SQL.
+    ///     The type parameters can be any document class, scalar or JSON-serializable class.
+    ///     For each result type parameter, the SQL SELECT statement must contain a ROW.
+    ///     For document types, the row must contain the required fields in the correct order,
+    ///     depending on the session type and the metadata the document might use, at least id and data must be
+    ///     provided.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <typeparam name="T1"></typeparam>
+    /// <typeparam name="T2"></typeparam>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameters"></param>
+    /// <returns></returns>
+    Task<IReadOnlyList<(T1, T2)>> QueryAsync<T1, T2>(char placeholder, string sql, CancellationToken token, params object[] parameters);
+
     /// <summary>
     ///     Asynchronously queries the document storage with the supplied SQL.
     ///     The type parameters can be any document class, scalar or JSON-serializable class.
@@ -51,6 +85,24 @@ public interface IAdvancedSql
     /// <returns></returns>
     Task<IReadOnlyList<(T1, T2, T3)>> QueryAsync<T1, T2, T3>(string sql, CancellationToken token, params object[] parameters);
 
+    /// <summary>
+    ///     Asynchronously queries the document storage with the supplied SQL.
+    ///     The type parameters can be any document class, scalar or JSON-serializable class.
+    ///     For each result type parameter, the SQL SELECT statement must contain a ROW.
+    ///     For document types, the row must contain the required fields in the correct order,
+    ///     depending on the session type and the metadata the document might use, at least id and data must be
+    ///     provided.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <typeparam name="T1"></typeparam>
+    /// <typeparam name="T2"></typeparam>
+    /// <typeparam name="T3"></typeparam>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameters"></param>
+    /// <returns></returns>
+    Task<IReadOnlyList<(T1, T2, T3)>> QueryAsync<T1, T2, T3>(char placeholder, string sql, CancellationToken token, params object[] parameters);
+
     /// <summary>
     ///     Asynchronously queries the document storage with the supplied SQL.
     ///     The type parameter can be a document class, a scalar or any JSON-serializable class.
@@ -62,6 +114,7 @@ public interface IAdvancedSql
     /// <param name="sql"></param>
     /// <param name="parameters"></param>
     /// <returns></returns>
+    [Obsolete(QuerySession.SynchronousRemoval)]
     IReadOnlyList<T> Query<T>(string sql, params object[] parameters);
 
     /// <summary>
@@ -77,6 +130,7 @@ public interface IAdvancedSql
     /// <param name="sql"></param>
     /// <param name="parameters"></param>
     /// <returns></returns>
+    [Obsolete(QuerySession.SynchronousRemoval)]
     IReadOnlyList<(T1, T2)> Query<T1, T2>(string sql, params object[] parameters);
 
     /// <summary>
@@ -93,6 +147,7 @@ public interface IAdvancedSql
     /// <param name="sql"></param>
     /// <param name="parameters"></param>
     /// <returns></returns>
+    [Obsolete(QuerySession.SynchronousRemoval)]
     IReadOnlyList<(T1, T2, T3)> Query<T1, T2, T3>(string sql, params object[] parameters);
 
     /// <summary>
@@ -109,6 +164,22 @@ public interface IAdvancedSql
     /// <returns>An async enumerable iterating over the results</returns>
     IAsyncEnumerable<T> StreamAsync<T>(string sql, CancellationToken token, params object[] parameters);
 
+    /// <summary>
+    ///     Asynchronously queries the document storage with the supplied SQL.
+    ///     The type parameters can be any document class, scalar or JSON-serializable class.
+    ///     For each result type parameter, the SQL SELECT statement must contain a ROW.
+    ///     For document types, the row must contain the required fields in the correct order,
+    ///     depending on the session type and the metadata the document might use, at least id and data must be
+    ///     provided.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameters"></param>
+    /// <returns>An async enumerable iterating over the results</returns>
+    IAsyncEnumerable<T> StreamAsync<T>(char placeholder, string sql, CancellationToken token, params object[] parameters);
+
     /// <summary>
     ///     Asynchronously queries the document storage with the supplied SQL.
     ///     The type parameters can be any document class, scalar or JSON-serializable class.
@@ -124,6 +195,23 @@ public interface IAdvancedSql
     /// <returns>An async enumerable iterating over the list of result tuples</returns>
     IAsyncEnumerable<(T1, T2)> StreamAsync<T1, T2>(string sql, CancellationToken token, params object[] parameters);
 
+    /// <summary>
+    ///     Asynchronously queries the document storage with the supplied SQL.
+    ///     The type parameters can be any document class, scalar or JSON-serializable class.
+    ///     For each result type parameter, the SQL SELECT statement must contain a ROW.
+    ///     For document types, the row must contain the required fields in the correct order,
+    ///     depending on the session type and the metadata the document might use, at least id and data must be
+    ///     provided.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <typeparam name="T1"></typeparam>
+    /// <typeparam name="T2"></typeparam>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameters"></param>
+    /// <returns>An async enumerable iterating over the list of result tuples</returns>
+    IAsyncEnumerable<(T1, T2)> StreamAsync<T1, T2>(char placeholder, string sql, CancellationToken token, params object[] parameters);
+
     /// <summary>
     ///     Asynchronously queries the document storage with the supplied SQL.
     ///     The type parameters can be any document class, scalar or JSON-serializable class.
@@ -139,4 +227,22 @@ public interface IAdvancedSql
     /// <param name="parameters"></param>
     /// <returns>An async enumerable iterating over the list of result tuples</returns>
     IAsyncEnumerable<(T1, T2, T3)> StreamAsync<T1, T2, T3>(string sql, CancellationToken token, params object[] parameters);
+
+    /// <summary>
+    ///     Asynchronously queries the document storage with the supplied SQL.
+    ///     The type parameters can be any document class, scalar or JSON-serializable class.
+    ///     For each result type parameter, the SQL SELECT statement must contain a ROW.
+    ///     For document types, the row must contain the required fields in the correct order,
+    ///     depending on the session type and the metadata the document might use, at least id and data must be
+    ///     provided.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <typeparam name="T1"></typeparam>
+    /// <typeparam name="T2"></typeparam>
+    /// <typeparam name="T3"></typeparam>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameters"></param>
+    /// <returns>An async enumerable iterating over the list of result tuples</returns>
+    IAsyncEnumerable<(T1, T2, T3)> StreamAsync<T1, T2, T3>(char placeholder, string sql, CancellationToken token, params object[] parameters);
 }

src/Marten/IDocumentOperations.cs

@@ -232,6 +232,15 @@ public interface IDocumentOperations: IQuerySession
     /// <param name="parameterValues"></param>
     void QueueSqlCommand(string sql, params object[] parameterValues);
 
+    /// <summary>
+    ///     Registers a SQL command to be executed with the underlying unit of work as part of the batched command.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameterValues"></param>
+    void QueueSqlCommand(char placeholder, string sql, params object[] parameterValues);
+
     /// <summary>
     /// In the case of a lightweight session, this will direct Marten to opt into identity map mechanics
     /// for only the document type T. This is a micro-optimization added for the event sourcing + projections

src/Marten/IQuerySession.cs

@@ -184,6 +184,7 @@ public interface IQuerySession: IDisposable, IAsyncDisposable
     /// <param name="sql"></param>
     /// <param name="parameters"></param>
     /// <returns></returns>
+    [Obsolete(QuerySession.SynchronousRemoval)]
     IReadOnlyList<T> Query<T>(string sql, params object[] parameters);
 
     /// <summary>
@@ -197,6 +198,19 @@ public interface IQuerySession: IDisposable, IAsyncDisposable
     /// <returns></returns>
     Task<int> StreamJson<T>(Stream destination, CancellationToken token, string sql, params object[] parameters);
 
+    /// <summary>
+    ///     Stream the results of a user-supplied query directly to a stream as a JSON array.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <param name="destination"></param>
+    /// <param name="token"></param>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameters"></param>
+    /// <typeparam name="T"></typeparam>
+    /// <returns></returns>
+    Task<int> StreamJson<T>(Stream destination, CancellationToken token, char placeholder, string sql, params object[] parameters);
+
     /// <summary>
     ///     Stream the results of a user-supplied query directly to a stream as a JSON array
     /// </summary>
@@ -207,6 +221,18 @@ public interface IQuerySession: IDisposable, IAsyncDisposable
     /// <returns></returns>
     Task<int> StreamJson<T>(Stream destination, string sql, params object[] parameters);
 
+    /// <summary>
+    ///     Stream the results of a user-supplied query directly to a stream as a JSON array.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <param name="destination"></param>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameters"></param>
+    /// <typeparam name="T"></typeparam>
+    /// <returns></returns>
+    Task<int> StreamJson<T>(Stream destination, char placeholder, string sql, params object[] parameters);
+
     /// <summary>
     ///     Asynchronously queries the document storage table for the document type T by supplied SQL. See
     ///     https://martendb.io/documents/querying/sql.html for more information on usage.
@@ -218,6 +244,19 @@ public interface IQuerySession: IDisposable, IAsyncDisposable
     /// <returns></returns>
     Task<IReadOnlyList<T>> QueryAsync<T>(string sql, CancellationToken token, params object[] parameters);
 
+    /// <summary>
+    ///     Asynchronously queries the document storage table for the document type T by supplied SQL. See
+    ///     https://martendb.io/documents/querying/sql.html for more information on usage.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="token"></param>
+    /// <param name="parameters"></param>
+    /// <returns></returns>
+    Task<IReadOnlyList<T>> QueryAsync<T>(char placeholder, string sql, CancellationToken token, params object[] parameters);
+
     /// <summary>
     ///     Asynchronously queries the document storage table for the document type T by supplied SQL. See
     ///     https://martendb.io/documents/querying/sql.html for more information on usage.
@@ -228,6 +267,18 @@ public interface IQuerySession: IDisposable, IAsyncDisposable
     /// <returns></returns>
     Task<IReadOnlyList<T>> QueryAsync<T>(string sql, params object[] parameters);
 
+    /// <summary>
+    ///     Asynchronously queries the document storage table for the document type T by supplied SQL. See
+    ///     https://martendb.io/documents/querying/sql.html for more information on usage.
+    ///     Use <paramref name="placeholder"/> to specify a character that will be replaced by positional parameters.
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    /// <param name="placeholder"></param>
+    /// <param name="sql"></param>
+    /// <param name="parameters"></param>
+    /// <returns></returns>
+    Task<IReadOnlyList<T>> QueryAsync<T>(char placeholder, string sql, params object[] parameters);
+
     /// <summary>
     ///     Asynchronously queries the document storage with the supplied SQL.
     ///     The type parameter can be a document class, a scalar or any JSON-serializable class.

src/Marten/Internal/Operations/ExecuteSqlStorageOperation.cs

@@ -12,17 +12,19 @@ namespace Marten.Internal.Operations;
 internal class ExecuteSqlStorageOperation: IStorageOperation, NoDataReturnedCall
 {
     private readonly string _commandText;
+    private readonly char _placeholder;
     private readonly object[] _parameterValues;
 
-    public ExecuteSqlStorageOperation(string commandText, params object[] parameterValues)
+    public ExecuteSqlStorageOperation(char placeholder, string commandText, params object[] parameterValues)
     {
         _commandText = commandText.TrimEnd(';');
+        _placeholder = placeholder;
         _parameterValues = parameterValues;
     }
 
     public void ConfigureCommand(ICommandBuilder builder, IMartenSession session)
     {
-        var parameters = builder.AppendWithParameters(_commandText);
+        var parameters = builder.AppendWithParameters(_commandText, _placeholder);
         if (parameters.Length != _parameterValues.Length)
         {
             throw new InvalidOperationException(

src/Marten/Internal/Sessions/DocumentSessionBase.cs

@@ -226,13 +226,18 @@ public void InsertObjects(IEnumerable<object> documents)
     }
 
     public void QueueSqlCommand(string sql, params object[] parameterValues)
+    {
+        QueueSqlCommand(DefaultParameterPlaceholder, sql, parameterValues: parameterValues);
+    }
+
+    public void QueueSqlCommand(char placeholder, string sql, params object[] parameterValues)
     {
         sql = sql.TrimEnd(';');
         if (sql.Contains(';'))
             throw new ArgumentOutOfRangeException(nameof(sql),
                 "You must specify one SQL command at a time because of Marten's usage of command batching. ';' cannot be used as a command separator here.");
 
-        var operation = new ExecuteSqlStorageOperation(sql, parameterValues);
+        var operation = new ExecuteSqlStorageOperation(placeholder, sql, parameterValues);
         QueueOperation(operation);
     }